Material: durable hard metal.Replacement Bottom Case Screws Set.This set of screws consists of ten screws that replace the screws of the bottom cover of Pro Unibody 13 inch 15 inch 17 inch.100% brand new and high quality Replacement Bottom Case Screws Set.Compatible models:for A1286 15 inch: Pro Core 2 Duo 2.4 late 2008for Pro Core 2 Duo 2.53 late 2008for Pro Core 2 Duo 2.53 mid 2009for Pro Core 2 Duo 2.66 early 2009for Pro Core 2 Duo 2.8 mid 2009for Pro Core 2 Duo 2.93 early 2009for Pro Core 2 Duo 3.06 mid 2009for Pro Core i5 2.4 mid 2010for Pro Core i7 2.0 early 2011for Pro Core i7 2.2 early 2011for Pro Core i7 2.3 late 2011 for A1278 13 inch: Core 2 Duo 2.0 late 2008for Core 2 Duo 2.4 late 2008for Pro Core 2 Duo 2.26 mid 2009for Pro Core 2 Duo 2.4 mid 2010for Pro Core 2 Duo 2.53 mid 2009for Pro Core 2 Duo 2.66 mid 2010for Pro Core i5 2.3 early 2011for Pro Core i5 2.4 late 2011for Pro Core i7 2.8 late 2011for Pro Core i7 2.7 early 2011for A1297 17 inch: Pro Core 2 Duo 2.66 early 2009for Pro Core 2 Duo 2.8 mid 2009for Pro Core 2 Duo 2.93 early 2009for Pro Core 2 Duo 3.06 mid 2009for Pro Core i5 2.53 early 2010for Pro Core i7 2.2 early 2011for Pro Core i7 2.3 early 2011for Pro Core i7 2.4 late 2011for Pro Core i7 2.5 late 2011for Pro Core i7 2.66 early 2010for Pro Core i7 2.8 early 2010Package Including:20 x Bottom Case Screws.Only the above package content, other products are not included.Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.