These 125mL PYREX Delong style shaker flasks have three baffle indents designed to provide greater agitation of solutions to improve oxygen or gas transfer when used with rotary or reciprocating shakers. The long neck reduces splashing and is designed for two-position polypropylene closures. Their uniform wall thickness provides the proper balance between mechanical strength and thermal shock resistance. For convenience, these flasks include a marking spot. The approximate neck O.D. is 25mm.