You are buying Genuine original Canon rear lens dust cap.  Buy one, get one free It comes with 30 days warranty. 

This cap is for use with Canon EF & EF-S mount auto focus lenses.

Rear Lens Cap For Canon EOS Lenses New 

 Rear lens cap for Canon  5D, 10D, 20D, 30D, Digital Rebel, Digital Rebel XT, and Digital Rebel XTi camera lenses.

This rear lens cap will fit Following EOS Digital ,autofocus , USM, EF, EF-s lenses.

Compatibility

-- EF 100 2.8 MACRO
-- EF 100-300mm f/4.5-5.6 USM
-- EF 100-400mm f/4.5-5.6L IS USM
-- EF 100-400mm f/4.5-5.6L IS USM Refurbished
-- EF 100mm f/2 USM
-- EF 100mm f/2 USM Refurbished
-- EF 100mm f/2.8 Macro USM
-- EF 100mm f/2.8 Macro USM Refurbished
-- EF 135mm f/2.8 with Softfocus
-- EF 135mm f/2L USM
-- EF 135mm f/2L USM Refurbished
-- EF 14 2.8 L USM
-- EF 14mm f/2.8L II USM
-- EF 14mm f/2.8L II USM Refurbished
-- EF 15mm f/2.8 Fisheye
-- EF 15mm f/2.8 Fisheye Refurbished
-- EF 16-35 2.8L USM
-- EF 16-35mm f/2.8L II USM
-- EF 16-35mm f/2.8L II USM Refurbished
-- EF 17-40 f/4L USM
-- EF 17-40 f/4L USM Refurbished
-- EF 180mm f/3.5L Macro USM
-- EF 20-35 3.5-4.5 USM
-- EF 200mm f/2L IS USM
-- EF 20mm f/2.8 USM
-- EF 22-55 4-5.6 USM
-- EF 24 1.4 L USM
-- EF 24-105mm f/4L IS USM
-- EF 24-70mm f/2.8L USM
-- EF 24-70mm f/2.8L USM Refurbished
-- EF 24-85 3.5-4.5 USM
-- EF 24mm f/1.4L II USM
-- EF 24mm f/2.8 IS USM
-- EF 28-105mm f/3.5-4.5 II USM
-- EF 28-135mm f/3.5-5.6 IS USM
-- EF 28-135mm f/3.5-5.6 IS USM Refurbished
-- EF 28-200mm f/3.5-5.6 USM
-- EF 28-300mm f/3.5-5.6L IS USM
-- EF 28-70 2.8L USM
-- EF 28-80 3.5-5.6 II
-- EF 28-80 3.5-5.6 V USM
-- EF 28-90 4.0-5.6 II
-- EF 28-90 4.0-5.6 USM
-- EF 28-90 4.0-5.6 USM II
-- EF 28-90mm f/4-5.6 III Refurbished
-- EF 28mm f/1.8 USM
-- EF 28mm f/1.8 USM Refurbished
-- EF 28mm f/2.8 IS USM
-- EF 300 2.8 L USM
-- EF 300mm f/2.8L IS II USM
-- EF 300mm f/2.8L IS USM
-- EF 300mm f/4L IS USM
-- EF 300mm f/4L IS USM Refurbished
-- EF 35-80 4.0-5.6 III
-- EF 35mm f/1.4L USM
-- EF 35mm f/1.4L USM Refurbished
-- EF 35mm f/2
-- EF 35mm f/2 Refurbished
-- EF 400mm f/2.8L IS II USM
-- EF 400mm f/2.8L IS USM
-- EF 400mm f/4 DO IS USM
-- EF 400mm f/5.6L USM
-- EF 500mm f/4L IS USM
-- EF 50mm f/1.2L USM
-- EF 50mm f/1.2L USM Refurbished
-- EF 50mm f/1.4 USM
-- EF 50mm f/1.4 USM Refurbished
-- EF 50mm f/1.8 II

- EF 50mm f/1.8 II Refurbished
-- EF 50mm f/2.5 Compact Macro
-- EF 50mm f/2.5 Compact Macro Refurbished
-- EF 600 4.0 L USM
-- EF 600mm f/4L IS USM
-- EF 70-200mm f/2.8L IS USM
-- EF 70-200mm f/2.8L IS USM Refurbished
-- EF 70-200mm f/2.8L Refurbished
-- EF 70-200mm f/2.8L USM
-- EF 70-200mm f/4L IS USM
-- EF 70-200mm f/4L IS USM Refurbished
-- EF 70-200mm f/4L USM
-- EF 70-200mm f/4L USM Refurbished
-- EF 70-300 4.5-5.6 DO IS USM
-- EF 70-300mm f/4-5.6 IS USM
-- EF 70-300mm f/4-5.6 IS USM Refurbished
-- EF 75-300mm f/4-5.6 III
-- EF 75-300mm f/4-5.6 III Telephoto Zoom Refurbished
-- EF 75-300mm f/4-5.6 III USM
-- EF 75-300mm f/4-5.6 III USM Refurbished
-- EF 8-15mm f/4L Fisheye USM
-- EF 800mm f/5.6L IS USM
-- EF 85 1.2 L USM
-- EF 85mm f/1.2L II USM
-- EF 85mm f/1.2L II USM Refurbished
-- EF 85mm f/1.8 USM
-- EF 85mm f/1.8 USM Refurbished
-- EF-S 10-22mm f/3.5-4.5 USM
-- EF-S 10-22mm f/3.5-4.5 USM Refurbished
-- EF-S 15-85mm f/3.5-5.6 IS USM
-- EF-S 15-85mm f/3.5-5.6 IS USM Refurbished
-- EF-S 17-55 f/2.8 IS USM
-- EF-S 17-55 f/2.8 IS USM Refurbished
-- EF-S 17-85mm f/4-5.6 IS USM
-- EF-S 17-85mm f/4-5.6 IS USM Refurbished
-- EF-S 18-55mm f/3.5-5.6 IS
-- EF-S 18-55mm f/3.5-5.6 IS Refurbished
-- EF-S 55-250mm f/4-5.6 IS
-- EF-S 55-250mm f/4-5.6 IS II
-- EF-S 55-250mm f/4-5.6 IS Refurbished
-- EF-S 60mm f/2.8 Macro USM
-- EF-S 60mm f/2.8 Macro USM Refurbished
-- EOS 60D EF-S 18-135mm IS Lens Kit
-- EOS 60D EF-S 18-135mm IS Lens Kit Refurbished
-- EOS 60D EF-S 18-200mm IS Lens Kit
-- EOS 7D EF 28-135mm IS Lens Kit
-- EOS 7D EF-S 18-135mm IS Lens Kit
-- Extender EF 1.4X
-- Extender EF 2X
-- MP-E 65mm f/2.8 1-5x Macro Photo
-- TS-E 17mm f/4L
-- TS-E 24 3.5L
-- TS-E 24mm f/3.5L II
-- TS-E 45mm f/2.8
-- TS-E 90mm f/2.8