HS35A encoders fit shafts from 1/2"to 1" easily, using a durable shaft insert.Models from 1/2" to 7/8" [12mm to 20mm] may be resized by replacing the insert, enabling our factory, distributors, and customer stockrooms to swiftly meet any need.The shaft insert also provides isolation from motor shaft currents, while permitting case grounding to meet NEC requirements. Avtron encoders have superior shaft seals and bearings that stay sealed to keep out contamination caused by temperature cycling and liquid sprays. Our encoder seals are protected by mechanical barriers to prevent flexing or failure, and Avtron's superior bearings feature synthetic lubricants for even longer life. Many competitive optical encoder designs risk sensor damage from any vibration or shock: sensors ride less than four thousandths of an inch from the thin, often flexible, optical disk spinning at full motor speeds. Some designs even use thin glass disks in "industrial" products! Avtron uses only unbreakable disks and a sensor to disk gap over 8X larger than the competition. Our optical HS35A encoders use superior sensor, disk, bearing, and seal technology to give top performance in industrial conditions. In many cases you cna replace competative models without rewiring. The encoder fits on end of shaft and through shaft applications. It can be supplied with a rugged protective basket. IP65/Nema 4, 13 Rating: Dust and Liquid Tight, -20°C to +100°C Operation allow us to offer it with a 2 Year No-Hassle Warrenty.