A memory upgrade is often the most inexpensive way to increase overall system performance. Crucial is part of one of the largest memory manufacturers in the world, and its premium-quality desktop memory is rigorously tested and delivers reliability at an affordable price. The name you can trust.Price-competitive, high-quality, and reliable, Crucial DRAM is backed by a limitedlifetime warranty and outstanding service and support. -333 MHz DDR1 - CL 2.5- Unbuffered - 2.5 Volts - Lifetime Warranty - 184 Pin DIMM- Apple IMac Compatible (Please check http://support.apple.com/kb/HT1423)