Why are the interiors of optical instruments black

Ear Cleaning Camera 1080P HD with LED Light, 8-in-1 Ear Pick Kit with Wireless App for Android iOS, Black

10X ABS Black + Gray Headband Magnifier Head Magnifying Glass Lens Loupe with LED Light and 3 Lens

Nautical Style Black Leather Telescope Maritime Brass Antique Double Barrel Designer Telescope Wooden Tripod Floor Standing Telescope.

1pc Black Optical Glasses 30xMagnifier Loupes Tool

Optical Wire Meter Tracer LCD Digital Network Cable Tester Rechargeable Network Line Finder Multifunctional Wire Tracker PoE Checker with Black Blue

1Pcs Black Pull Automatic Pop Up Jewelry Magnifier With Led Light

LED Magnifying Magnifier Glass with Light On Stand Clamp Arm Hands Free Black

Portable USB2.0 Digital 2 Million Pixels Practic Magnifier Microscope Camera Black

Portable Digital Microscope 50X To 1000X Zoom HD Microscope 3 In 1 USB Magnifier 8 LED Lights Black

Convenient Magnifier Precision Multi-function Black Practical LED Magnifier for Collecting

Ulefone Endoscope E2 IP67 Waterproof Digital Endoscope for Ulefone Armor 9 / 9E / Power Armor 13 / 16 Pro / 18T / Armor Pad(Black)

Universal Car Modification Instrument Rack: 52MM Black Dual-Hole Perforated Cover

16X52 Monocular Telescope Outdoor HD Pocket Travel Tools Plastic Waterproof Tourism Scope Binoculars Black Telescope Travel Tool

LED Magnifying Glass Black Round 10x Hand Held Magnifier with Light for Office School Outdoor Home

Ultra-Thin A4 Black PVC Frame Bendable 3x Full-Page Reading Magnifier

Dashboard Sunshade Dashmat Cover Anti Slip Black Trim Instrument Panel Protector Mat Replacement

4Pcs Eye Loupe Magnifying Glass Portable 5x 10x 15x 20x Black Professional Jewelers Loupes

Microscope Eyepiece Eye Piece Lens High Point Adjustable Visibility 30mm Interface Black

AmazonBasics Camera Bag for SLR X X Cm Black Color Plain 32.4 20.3 24.8 (Interior Orange)

Ulefone uSmart C01 Wired Digital Microscope for Ulefone Armor 18 Series / 9 / 9E & Power Armor 16 Series / 13 / Armor Pad(Black)

Working Antique Design Table Decor Black Chrome Tripod with Telescope Stand Gift

5P0081 Black Refraction Astronomical Telescope Accessory 0.965 Inch 45 Degrees Diagonal Mirror

Handheld Magnifying Glass 3X Magnification Portable Elderly Reading Writing Magnifier Black

1pc Black 15Meter USB Endoscope with 2Megapixel Waterproof Camera for Pipe Car Inspection

ABS Black Digital Infrared Night Vision Monocular Telescope with Screen CCD Kit for Day Night Using

Astronomical Telescope 8‑24mm Continuous Zoom Eyepiece Observation 1.25inch31.7mm Black

13in 60FS 1080P Black HDMI Output Industry Microscope Camera DC5?12V

Black 7in Optical Time Domain Reflectometer Multifunctional OTDR Tester 1310 1550nm 32 30dB

Single Barrel - Portable for Outdoor Adventures, Safaris, Trips, and Concerts - the Perfect Gift for Halloween, Christmas, and Black Friday.

Black Metal 40mm 1.25inch Multilayer Wideband Coating Monocular Eyepiece for Astronomical Telescope

Microscope with Smartphone Adapter LED Light Compact Portable WSA White X Black Do Nature 60-120x Built-in STV-120M

4 Pieces Eye Loupe Jewelers Clip Magnifying Glass Black Repair Tool Magnifier

1.25inch 90 Degree Black Erect Image Lens Astronomical Telescope Universal Accessories

5X Magnifying LED Light USB Adjustable Light for Beauty Salon Nail Art Tattoo Black

Fashionable Metal Guitar Keychains Black White Guitar Heart-shaped Buckle Couple's Musical Instrument Key Holder

Handheld USB Microscopes 50X‑1000X Mini WiFi USB Black Wireless Digital Microscope with 8 LED

Argo File 10x Stereo Binocular Microscope Great Eye Black with LED Light

Black 3X 4X 5X Jeweler Watchmaker Loupe Loupes , Black,

4X Hanging Neck Magnifying Glass Flexible Gooseneck Large Page Magnifier for Reading Repair Black

Eye Loupe Magnifier 5X No. 4422 Model 2 Mag Watch Jewelry Repair Tool Plastic Black

Wireless Digital Microscope 50X To 1000X USB Mini Black Handheld Microscope with 8 LED Lights for

Earpick Endoscope 6 LEDs 1080P IP67 Waterproof One Button Control App Support Black Ear Cleaner for

Microscope Camera 144 LED Beads Light Source Brightness Adjustable Ring Lamp (Black)

Black 3X 4X 5X Jeweler Watchmaker Loupe Loupes , Black,

USB Clip On Magnifier Lamp Tattoo Foldable 5X Magnifying Glass Led Lamp for Home Beauty Salon(Black

LED Magnifying Glass Double Lens Black White 3 LED Lights Portable Illuminated Lighted Magnifier

LED Clip‑On Magnifying Light 5X Magnifier Lamp for Embroidery Engraving Black

Soldering Iron Station Stand Welding Magnifying Glass Clip Clamp 3Hand Desktop Magnifier Solder White/Black 185*95x240mm

200X Phone Microscope Black Portable USB Charging 110mah with CPL Filter Phone Microscope Lens

2-inch (52mm) Black Carbon Pattern Car Instrument Cup Holder

Working Antique Design Table Decor Black Chrome Tripod with Telescope Stand

Jewelers Eye Loupe Magnifier 10X Red and Black Lightweight Magnifying Glass Jewelry Watch Repair

Astronomical Telescope 7‑21mm Continuous Zoom Eyepiece Observation 1.25 Inch31.7 MM Black

Reading Glass Loupe Elder Big Lens Magnifying Black Frame Hot Sale Eyewear Clear Lense Magnifier

15.24 Cm Telescope with Black Leather Stitched With Wooden Box

Handheld Magnifying Glass 20X Optical Magnifier with 21 LED Lights USB Charging Touch Switch Black

Magnifying Glass Adjustable LED Independent Research Set, Monocular, 100x, 400x, 1200x, Angle, Light, Plant, Gems, Observation, (Black)

1pc Portable A4 Full Page Magnifier Black Frame Ultra Thin Magnifying Glass Bookmark Magnifying Lens For Reading Books

Working Antique Design Table Decor Black Tripod with Telescope Stand

Elder Eyewear Hot Sale Black Frame Reading Glass Loupe Magnifying Big Lens Clear Lense Magnifier

Nautical Desktop Standing Brass, Leather Telescope Anchor-Master Decorative Home Decor, Black Brass Finish

2inch Durable Telescope Eyepiece 40mm Extension Tube M48 Thread Adapter Black

Black 4mm 1.25" 58 Degree Planetary Deep Sky Objects Eyepiece For Telescope JS

Nautical Style Black Leather Telescope Maritime Brass Double Barrel Designer Telescope Wooden Floor Standing Tripod

200X Phone Microscope Black Portable USB Charging 110mah with CPL Filter Phone Microscope Lens Magnifier for Biological Science Observation

2" To 1.25" Telescope Eyepiece Mount Adapter Black Metal Accessories Adaptor

Black High Quality Magnifying Glass Lens Reading Hobbies for Low 3X 4X 8 Diameter 50mm 65mm 75mm ,

AmazonBasics Camera Bag for SLR 32.4 X 20.3 X 24.8 Cm Black (Orange Interior Color) Plain

10x Black LED Instrument Bulb For Automotive – Easy Installation High Brightness And Long Lifespan

With Light Black Acrylic Glass Reading High Magnification LED UV Lens 30X 60X 90X Magnifier

Reimei Fujii Microscope Handy Microscope DX Black RXT1144B

Stereoscope Cheiroscopes Adjustable Amblyopia Trainer Vision Tester Tools for Heterotropia Squint Black

3X 10X Neck Magnifying Glass Round Flexible Gooseneck Reading Magnifier for Repairing Sewing Black

Black LCD Dashboard Cluster Dashboard Instrument LCD Screen

Inch 3 Full Black Multi Coated with M42x 0.75mm Thread for Standard Eyepiece Astronomy

USB 0.3MP Telescope Electronic Eyepiece Digital Camera Inch/31.7mm (Black)

Car Air Conditioner Outlet Finisher-Instrument Panel Air Conditioning Vents Cover Shell for Nissan Tiida 2005-2011 Black

Guide Scope for Telescope Astronomy Accessory Professional Black Finderscope

BeaverLab TW1 Smart Astronomical Telescope 500mm 1080p F/6.1, Resolution, Black.

Black Music Instrument Camera Rotating Adjustable Bracket Fixed Clip Accessories for Gopro Sports

NAKOBO Automotive T5 Socket Meter Socket LED Socket Black Instrument Panel Cluster Light Bulb Pack of 10

1Pcs Black Instrument Speaker Cover Dashboard Top For J1aguar XF 2008-2015 C2Z1835LEG

Brass Nickel Telescope Binoculars Black Lather 7-inch Best for Gift Item

Piano Chair Piano Chair Electronic Piano Keyboard Chair Chair Stool Music Lesson Practice Lessons Performance Interior Height Adjustment Cushion Black