These flasks feature deep-fluted sides to promote mixing. A dam below the sidearm retains untrypsinized tissue when decanting. A deep-skirted screw cap on the sidearm prevents contamination of flask contents. The sidearm allows easier decanting of contents while retaining large particles behind the dam. Sidearm caps are 20-415 size. Caps have white styrene-butadiene rubber liners. Flasks are made from Wheaton 33® low extractable borosilicate glass (meets ASTM Type I Class A and USP Type I standards).