This elbow has a silicon gasket and an integral gear clamp on the female end
Z-Flex Z-Vent 3" x 45 Degree Elbow Stainless Steel Venting (2SVEEWCF0345). Z-Flex Z-Vent stainless steel vent pipe is ideal for the Bosch Therm 940ES / Bosch Therm 830ES / Bosch Therm 660EF / Bosch AquaStar 2700ES / Bosch AquaStar 2400ES / Bosch Evolution 500 tankless water heaters as well as the legacy Bosch Pro 715ES / Bosch Pro 635ES / Bosch AquaStar 2400E / Bosch AquaStar 250SX heaters. Z-Flex Z-Vent is rated AL29-4C and is approved for Category I (vertical only), II, III & IV applications and is designed for use with boilers, high efficiency gas and oil heaters and water heaters where cool flue gases are vented under pressure. Z-Vent contains a built-in, fail-safe gasket and locking band connection. No sealant is required.