Description:The rear lens cap is used when storing your lens or after the lens has been removed from your camera. It helps to keep dust from your lens mechanism.This metal cap is perfect for any M42 Screw mount lens such as for Asahi Pentax Super Takumar and any other M42 screw mount lens.Specification:Material: Anodized Aluminum AlloyMount Type: Standard M42×1 ThreadThread Pitch: 1mmInstallation: Simple Screw-in DesignWeight: 16gColor: BlackCompatibility: Designed for cameras and lenses with the universal M42×1 thread screw mount, such as for Pentax, zenit, carl zeis, other mirror lens etc. Important Note:Caution: This cap is NOT compatible with the M42×0.75 thread standard sometimes used in astronomical equipment and other specialized devices. Please verify your thread pitch before purchase. Package included:1 x Metal Rear Lens Cap 【Durable Aluminum Alloy Construction】 Made from high-quality, machined aluminum, these M42 caps are built for longevity. They are shatter-proof, bend-resistant, and offer far superior protection compared to flimsy plastic caps, ensuring your lens mounts stay safe. 【Precision M42 Screw Mount】 Features accurately machined M42 x 1mm threads for a perfect, secure, and smooth fit. Designed to prevent cross-threading, these caps reliably protect the valuable threads on your vintage M42 mount lenses. 【Complete Dust & Scratch Defense】 Effectively seals your lens rear elements from dust, moisture, fingerprints, and accidental scratches. This simple upgrade is crucial for maintaining the value and optical performance of your cherished photography equipment. 【Lightweight & Sleek Black Finish】 The solid metal build feels premium without adding significant weight. The anodized black surface provides a corrosion-resistant, non-reflective, and professional appearance that complements any classic or modern camera gear. 【Perfect Fit for M42 System】 This M42 rear lens cap is ideal for all lenses with the universal M42 screw mount, including classic models for Pentax takumar, for Praktica, for Zenit, for Helios M42 lenses and more. ASIN B0FY6YMHS3 Item Weight 0.634 ounces Manufacturer AIToWisely Package Dimensions 4.92 x 4.25 x 0.51 inches