Takes a few initial pumps to prime the device and for the gauge to start increasing in pressure. Tried it on the bathtub drains and the water started to flow more freely down the pipes! Instructions could be a bit more clear, but after you figure it out, it's not hard to operate.

Interesting product

works good

Only had to use once so far on a sink but it worked like a charm

get them on sale, they're great

Bought a second one. It's great aside from the hollow handle that seems like it'll be the first to break when it does.