I recently saw a new Visonic sensor MCT - 350 when a buddy had his Xfinity alarm system installed. I googled them and found some for sale on eBay and went ahead and ordered one to test with ST. I found a Visonic DTH on github and installed it and when I activated the sensor it showed right up in ST and has worked flawlessly ever since.
Visonic (Tyco is the parent company) claims that these new sensors will last 5 years on the CR2450 Panasonic battery which would be great but I’m not holding my breath (even if it’s 2-3 years it would be great).
The seller has them on sale for 1/$19.99 or 6/$100 so I ordered 12 more and each one of them has worked perfectly since installing them.
Lastly, they are designed to bridge even wider gaps when a standard Visonic sensor won’t cut it.
Search eBay for Visonic / Tyco Magnetic Door Window Sensors XHS2- TY Xfinity Wireless Zigbee and the sellers listing should come right up
Edit - here is the link for them but it seems the seller has ended the sale (maybe contact the seller if purchasing multiple and ask if they would honor the previous sale price?) Visonic / Tyco Magnetic Door Window Sensors XHS2- TY Xfinity Wireless Zigbee New