Humidistat, if available which I don’t think it is anymore, last price check was over $1,000 over a year ago. Helps remove moisture, was in good working order when removed from an air compressor that had compressor head failure that decommissioned it . If compressor keeps cycling without rest & unloaded & check valve are ok, open electrical control lid. If air leak is coming from humidistat, then it simply needs to be replaced. It’s much cheaper than a new compressor costing over $10,000 in most cases. Fits AS 10, AS 21, AS 30, AS 50 & AS 70 models I have 4 of them for sale, only 1 included in this listing