Suitable for carburetors of chainsaws, blowers, trimmers with a ratchet primer system such as McCulloch, Craftsman, Husqvarna, Poulan. Sears, Echo, Troy Bilt, Weed Eater, Ryobi, Stihl, Ryan and more. High quality replacement primer bulb. Replaces Walbro 188-512 188-512-1. Refer to part numbers 01183, UP04033, 300780001, 300780002 and 300780004. Replaces mtd 791-683974B, ryobi, 683974B, oregon 49-088-0, location number 188-512. Height: 31.4 mm, width: 21.4 mm. Primer bulb for chainsaws, blowers, high pressure cleaners, weed cutters and brush cutters Pouland, Homelite, Sears, Craftsman, with a ratchet primer system. A primer bulb Clear primer in a black plastic base with two fuel tips (one shorter than the other), and two clasps that snap into place. Please check images for compatibility before ordering , we place great confidence in the quality of our parts.