Interested if anybody has a source for purchasing the good Zama snap in type prime bulbs with the normal ear spacing on the back not interested in the wider stance bulbs intended for some br 600 blowers as well as the ts420 demo saws . Only interested in the normal ones. The Zama bulb seems to have a tougher rubber as well as the duel check valve set up which is darn near bullet proof when decent fuel is used. The walbro bulbs swell and crack prematurely and in my eyes are a waste of money. Stihl is using these heavy duty bulbs on the ms251 easystarts as well as everything else with a primer in the product line which makes me believe the good snap in bulbs are a product of Zama. Since we all know Stihl owns them. Interested to hear from anybody that knows a bulk source we go thru a fair amount of primer bulbs in a years time and are looking to outfit our customer with a longer lasting more reliable part at half the cost that stihl is charging I’m sorry 13 dollars for a plastic prime bulb is unreal