The TRW Power Brake Booster - PSA921 is a high-quality brake booster designed for use in various vehicles. It is manufactured by TRW, a trusted brand in the automotive industry. This brake booster is designed to improve the braking performance of your vehicle by providing additional force to the brake system. It is made with durable materials and advanced technology to ensure reliability and longevity. The PSA921 model is specifically designed for use in PSA vehicles, but it can also be compatible with other makes and models. This product is easy to install and is a cost-effective solution for improving your vehicle's braking system.