Well guys I'm trying the old X-40 valve on my x40 this morning..fingers crossed. The valve fit right in there. The release hole on the 40 keeps letting in air...getting big bubbles. I've tried everything. So I'm happy with the gains the herc gave me, solid 1/4 girth, 0 length. The x40 valve is a rectangle release, the X-40 is square. So I'm thinking that locking crap is the reason for the air intrusion. Well gonna blow up Mr. Peterson n report back. Today.