Ball valves Ball valves with GL screwthread made of chemically resistant PTFE. Maximum permissible atmospheric temperature 150°C, passing media can be as hot as 220°C. The special construction allows the clamps to be used under pressures of up to 10 bar and also under vacuum. A further advantage is that they can be used as expansion/reduction adapters to connect tubing of different diameters. For easy tubing connection we recommend the accessory Bola laboratory screwthread connection which can be ordered separately.