Originally Posted by taz2005

Hi Mark
In the manual that came with the pump (which I ordered from Eurcharged to make sure I got the right one) it says
CM10P7-1 has the 16 mm connection and
CM30P7-1 has the 20 mm connection. (One I got for the SRT-6). There are 2 different types of the CM30P7-1 noted in the manual but the difference is voltage 12V or 24V not connection size. Hope this helps.