Final comment I'd have is that leak sensors are one place where I believe it makes sense prioritize quality/reliability rather than price. The downside of a contact sensor not firing is a little inconvenince (light doesn't turn on or off) but if your leak sensor goes offline, or doesn't report when wet, there can be very significant consequences.
These Centralite sensors are based on a time-tested design and at $29 on Amazon are reasonably priced.
https://www.amazon.com/gp/product/B072DYHPY7/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
Good thread here on leak sensor options:
