"Bought 2 sets, one for a MS310 and one for a MS311. Both fit perfectly and don’t leak. Proline® fuel and oil cap EZ-Twist™ for many Stihl chainsaws. Much simpler to use. EZ-Twist™ Cap (2pcs). Note: MS440 will fit a bit tight on the first few tries but will fit better as you use it.
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