Ikelite 4-40 Hex Head Allen Wrench Tweet Description This 4-40 Hex Head Allen Wrench from Ikelite is used to tighten or loosen hex head screws on select underwater housings. Details Additional Category Tags: Equipment Accessories, Misc. Accessories Category: Photography Manufacturer Catalog Number: 945.11 Product Manufacturer: Ikelite Subcategory: Underwater Photography