The A-Tech 2GB Memory stick was specifically engineered to be compatible with the PANASONIC TOUGHBOOK 51 CORE DUO CF51RCLDFBM. Included in the package is a single 2GB A-Tech DDR2 PC2-5300 1.8V (JEDEC Standard DDR2 Operating Voltage) NON-ECC Unbuffered SO-DIMM Memory Module (200-pin SO-DIMM 667MHz). Serves as a compatible replacement or expansion of existing OEM installed modules. A-Tech is one of the most trusted names in Premium Memory. Backed by a Lifetime Warranty and 5 star customer support, A-Tech has you covered! Memory upgrades have never been easier. Designed specifically to help your computer run faster and smoother, an A-Tech memory upgrade is one of the fastest, most affordable, and easiest ways to improve your system's performance. A-Tech memory empowers your computer to achieve faster application loading times, faster system responsiveness, and increased ability to multitask and handle data-intensive programs. A-Tech modules are rigorously tested to ensure that your memory meets our stringent compatibility and performance standards. Every A-Tech ram module is tested for complete functionality before it leaves our doors. Give your computer the best, trust A-Tech!