The product is a bundle of 512MB vintage RDRAM PC800 non-ECC RAM modules, made by Samsung and PNY. Each module has a capacity of 128MB, and there are a total of 4 modules in the bundle. The bus speed of these modules is PC-800, providing high performance for older computers that support RDRAM memory technology. This RAM bundle is ideal for those looking to upgrade their computer's memory capacity with reliable brands like Samsung and PNY.