The NeaterHeater Pro magnets can be split in two. I've seen several people with issues on the long glass ones having alot of torque on the mount. This causes a heater to rotate anytime the cord is bumped. Splitting the magnets solves that.
The other issue is I bought one thag didn't hold my heater years ago and had to buy a whole new unit that, I thought was stronger. In this case a person could buy a regular and simply add as many magnets as floats your boat without having to water a prior purchase.