Excerpt: Sony ALCR55 Rear Lens Cap Features The ALC-R55 rear lens cap is designed to fit securely over the back end of your Sony α (alpha) DSLR-A100 camera lens. The rear lens cap protects the interior from dust, smears and debris when a lens is not in use. Product Specifications Limited Warranty: none Weight (Approx.): 13.5g (0. 5oz) Dimensions (Approx.