We use & sell those in the pet store I work in, and they work well enough. I've never heard anyone complain about them, and we have some that have been running over a year and a half in the store. But, in general, I don't recommend Penn-Plax. They produce a lot of cheap products. I say spend the extra couple bucks and get something decent. I'm pretty sure my Jager was $20 from Drs. F&S.