WonderPana 145 System Core & Lens Cap - 145mm Filter Holder for The Tokina 16-28mm f/2.8 at-X Pro FX Lens (Full Frame 35mm) Premium Grade Anodized Aluminum WonderPana 145 Core Unit 145mm x 1mm Standard Thread Enabled Finely Crafted, Heavy Duty Inner Pinch Lens Cap Variety of 145mm Round Filters Available 24-Month Manufacturer Warranty