A system and method are disclosed for controlling transmitter output levels in a wireless communications device. In a first type of system, a first wood product has a first chemical compound applied to a surface of the first wood product. By comparing the cart’s tracked movement to known symptomatic movement patterns, the system may identify defective or damaged carts. The latter has a casing with three chambers, the middle one of which is separated from the first outer one by a grid and from the other by a hydrophobic drainage layer.