Product review (5 stars): As Good As the Original, and Does the Job
I purchased this pad as a replacement for a Honeywell HE360A humidifier. It appears to be identical to the original one that came with the humidifier in the box. In my case there is a black plastic frame into which the pad is positioned. Tabs on 4 sides release to allow the pad to be changed. Pop the frame with new pad back into place and you're done. I experienced no leaks or issues and humidifying performance was the same as it was initially.

The "official" recommendation is to replace the pad twice during the heating season. The reason, as I quickly found out, is that mineral deposits from the water tend to accumulate on the pad over time. In extreme cases it turns into large particles of dust that clog the pad and reduce efficiency - same as a clogged air filter. My experience with Colorado water confirms that twice-a-winter recommendation is reasonable, though your water conditions may vary. A good examination every month along with your HVAC filter is prudent.

It came shipped in a large box with appropriate padding which is a good idea since impacts will damage it. The price on Amazon is almost always $1 less than what you see in most home improvement stores. Without sales tax and with free shipping you'll come out ahead. Overall I'm happy.