- Easy Installation and Durability: Our R Bulbs Fuel Pump Primers for FS 300, FS 350, FS 400, and FS 450 are designed for straightforward installation and long-lasting performance. You can install them effortlessly without any complications. - Perfect Aftermarket Replacement: These R Bulbs Fuel Pump Primers serve as an ideal aftermarket replacement for your FS series trimmers. They are meticulously crafted to meet the specifications and requirements of your FS 300, FS 350, FS 400, and FS 450 models. - Dual Bulbs Included: This package includes two R Bulbs Fuel Pump Primers. The dual bulbs ensure reliable and consistent fuel flow, enabling your trimmers to operate efficiently and effectively. - Optimal Dimensions: Our R Bulbs feature a pump glass diameter of 15 mm and an overall diameter of 21 mm. The distance between the snap fittings is precisely measured at 17 mm, ensuring a perfect fit and seamless operation with your FS trimmers. Use Scenarios: - Ideal for maintaining your lawn and garden with optimal trimming performance. - Perfect for professional landscapers who need reliable equipment for daily use. - Great for DIY enthusiasts looking to keep their outdoor tools in top shape. This product is built to enhance the functionality of your FS series trimmers, providing a dependable fuel supply for optimal performance.