I just got a preview of the Wilkins 350 three-quarter and one-inch double check valve assembly and found it to be something worth thinking about. Apparently this device took a couple of years to pass the USC inspection. First of all, from end to end, the 1 DCVA is only 12 ¼ inches in length. The ¾ DCVA is 11 in length. Ive been using the 1 950 XLT DCVAs and theyre 14 ¾, which can be tight in a standard valve box, especially when you add unions and other stuff to the line. This 350 has the two check valves in a modular type of assembly that can be easily removed by unscrewing four screws. The rep told me that they plan on having a winterizing blowout stub attachment that would attach to the DCVA where the check valve module is. That is a different approach and something I havent thought of. It looks as if this little guy could surely simplify installs, and by removing the check valve module when winterizing that would pretty well eliminate any need of having to blow air through the checks to get water out.