Convert wide mouth Mason jars into drinking cups easily with these sustainable bamboo mason jar lids with straw holes. Size: Fits wide mouth, 3 in (76 mm) inner and 3 3⁄8 in (86 mm) outer diameter, versions. The straw hole is 0.56". Mother Earth Approved: Made from high quality and smooth, naturally antimicrobial bamboo, this is a great addition or gift for those trying to live more sustainably.