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" 15" 17". and high quality Replacement Bottom Case Screws Set. Compatible models: A1286 15 ": Pro Core 2 Duo 2.4 late 2008 Pro Core 2 Duo 2.53 late 2008 Pro Core 2 Duo 2.53 mid 2009 Pro Core 2 Duo 2.66 early 2009 Pro Core 2 Duo 2.66 mid 2009 Pro Core 2 Duo 2.8 late 2008 Pro Core 2 Duo 2.8 mid 2009 Pro Core 2 Duo 2.93 early 2009 Pro Core 2 Duo 3.06 mid 2009 Pro Core i5 2.4 mid 2010 Pro Core i7 2.0 early 2011 Pro Core i7 2.2 early 2011 Pro Core i7 2.3 late 2011 A1278 13 ": Core 2 Duo 2.0 late 2008 Core 2 Duo 2.4 late 2008 Pro Core 2 Duo 2.26 mid 2009 Pro Core 2 Duo 2.4 mid 2010 Pro Core 2 Duo 2.53 mid 2009 Pro Core 2 Duo 2.66 mid 2010 Pro Core i5 2.3 early 2011 Pro Core i5 2.4 late 2011 Pro Core i7 2.8 late 2011 Pro Core i7 2.7 early 2011 A1297 17 ": Pro Core 2 Duo 2.66 early 2009 Pro Core 2 Duo 2.8 mid 2009 Pro Core 2 Duo 2.93 early 2009 Pro Core 2 Duo 3.06 mid 2009 Pro Core i5 2.53 early 2010 Pro Core i7 2.2 early 2011 Pro Core i7 2.3 early 2011 Pro Core i7 2.4 late 2011 Pro Core i7 2.5 late 2011 Pro Core i7 2.66 early 2010 Pro Core i7 2.8 early 2010 Package Including:10 * Bottom Case Screws 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.