After the flange is complete, the end must be heated again to the softening temperature and cooled slowly, to prevent it from cracking.
"Laboratory Manual of Glass-Blowing"
Francis C. Frary
He gripped the mouthpiece of his snorkel between his teeth, the rubber flange under his lips, and slid into the water.
"The Wailing Octopus"
Harold Leland Goodwin
The sun was still hidden from us behind the mountain flange on our left; the snow patches on the sky-line ahead seemed comparatively near, and the diabolical swiftness of the shikari's stealthy walk was yet to be fully realised.
"A Holiday in the Happy Valley with Pen and Pencil"
T. R. Swinburne