Micromatic Model M Standard Response, Standard Coverage Upright Glass BulbSIN VK100, K Factor: 5.6 (81) Thread Size: 12 inch NPT Thread.Install using Viking 10896WB standard wrench or wrench 13577WB for waxed or recessed applications. Select Temperature Rating from Dropdown Menu. Viking Upright Fire Sprinkler Heads and Conventional Pendent Fire Sprinklers are small, thermosensitive, glass-bulb spray sprinklers available in several different finishes, temperature ratings, and K-Factors to meet design requirements. The special Polyester and Teflon coatings can be used in decorative applications where colors are desired. In addition, these coatings have been investigated for installation in corrosive atmospheres and are UL listed as corrosion resistant .