The Closed Port P/C's came on some of the Husqvarna 55 EPA saws. They will have a compression release and easily identified by the +++++++++ across the bottom of the jug.
I have two of them here, they have great power for the cc's and my "go-to" saws for limbing and most of the tops I'm cutting these days. The power curve is narrow and strong not wide/broad/flat like the 55 Rancher open port 55's. I'm really fond of all the Husqvarna 55 platforms and wouldn't stick my nose up at a 55 Rancher open port in good shape. Even with that said if you had a closed port and open port 55 laying there and headed to the woods to cut some firewood unlikely you'd find yourself reaching for the open port version......IMHO.......
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