ProMaster 52mm SystemPro Professional Lens Cap 4543 The SystemPro Professional Lens Cap is MORE than your everyday lens cap. ProMaster SystemPro Lens Caps are precision molded for optimum fit and use a center activated locking system that aids in the secure fit of the cap. ProMaster 1-Year Limited Warranty Included Supplied Accessories: ProMaster 52mm SystemPro Professional Lens Cap