Use above the tee to provide support when bypassing obstructions or overhangs. Supports up to 20’ of chimney. Tee Support is not necessary when using this support. For 5” diameter, it adjusts from 8 1/2” to 15 1/2”. For 6” diameter, it adjusts from 8” to 15”. For 7” diameter, it adjusts from 7 1/2” to 14 1/2”. For 8” diameter, it adjusts from 7” to 14”.