Watch Glass
Gelsonlab HSCG-1175 Laboratory Sapphire Double Dome 1.0mm Edge Thick Watch Crystal Concave Watch Glass Plain Watch Glass Beaker Cover
Size 17mm, 17.5mm, 18mm, 18.5mm, 19mm, 19.5mm, 20mm, 20.5mm, 21mm, 21.5mm, 22mm, 22.5mm, 23mm, 23.5mm, 24mm, 24.5mm, 25mm, 25.5mm, 26mm, 26.5mm, 27mm, 27.5mm, 28mm, 28.5mm, 29.5mm, 29mm, 30mm, 30.5mm, 31mm, 31.5mm, 32mm, 32.5mm,, 33mm, 33.5mm, 34mm, 34.5mm, 35mm, 35.5mm, 36mm, 36.5mm, 37mm, 37.5mm, 38mm, 38.5mm, 39mm, 39.5mm, 40mm(there might be ±0.05mm difference for diameter)