Filter tapes, filters, PM inlets etc. are sold by independent manufacturers. However - please read below. Only authorized inlets, filter tape and other Met One Instruments' fully tested spare parts and consumables may be used in our instruments. Many vendors sell PM10 and PM2.5 type inlets, filter tape etc. but, we take our instruments through vigorous and comprehensive tests to guarantee regulatory compliance as well as the best performance for our products. Any unauthorized substitutions will void any MOI warranty as well as void regulatory compliance designations or certifications. This applies to all products which have gone through extensive testing to be certified in agencies around the world. Questions? Contact: dgobeli@metone.com or joann@metone.com.