Gas detector in industrial refrigeration processes and biological degradation processes, including exhaled breath. Depending on the required sensitivity, different types of sensors are used (e.g., flame ionization detector, semiconductor, electrochemical, photonic membranes). Detectors usually operate near the lower exposure limit of 25ppm; however, ammonia detection for industrial safety requires continuous monitoring above the fatal exposure limit of 0.1%. There are several different sensors that can be installed to detect hazardous gases in a residence. Carbon monoxide is a very dangerous, but odorless, colorless gas, making it difficult for humans to detect. Carbon monoxide detectors can be purchased for around US$20–60. Many local
Poulan featured in the 1974 movie "The Texas Chain Saw Massacre". The Poulan brand name is used primarily for outdoor power equipment, such as chainsaws, lawn mowers, and leaf blowers, aimed at the mid-level consumer market. Since Poulan is owned by Husqvarna, the two brands often share technologies. In recent years Poulan has offered a more upscale "Poulan Pro" brand employing a black and gold color scheme instead of Poulan's traditional green. As a result, Poulan products have been pushed even further upmarket. Along with Poulan, Jonsered and Husqvarna brand products, Husqvarna also provides lawn mowers, lawn tractors, and other yard