What uses 433MHz frequency?

The ISM radio bands are portions of the radio spectrum reserved internationally for industrial, scientific and medical (ISM) purposes, excluding applications in telecommunications .

433MHz is a commonly used frequency band for all types of equipment that require little power, such as garage door openers, headphones, baby phones and remote controls . Also many inexpensive transmitters and receivers for switching devices and light dimmers operate on the 433MHz band.

The lower frequency radio waves of 900 MHz radios provide greater penetration through walls, trees and other obstacles, making it optimal for most non-line-of-sight applications. A typical AW900xTR Radio using high powered AW-15 15dbi antenna can go distances of up to 1500 feet with buildings and/or trees in the way.