CRL 1/8" x 3" Aluminum Horseshoe Shims - 100 Pack For Use When Installation of Plastic Shims is Restricted by Building Codes Won't Compress Under Heavy Aluminum Base Shoe Available in Three Thicknesses: 1/16", 1/8", and 1/4" (1.6, 3.2, and 6.3 mm) 6061-T6 Aluminum Alloy