Extra Caps and Septa

Additional screw caps and septums are conveniently packaged for use with the Screw Thread sample tubes. White silicone rubber lined solid caps resist most solvents; Teflon lined solid caps (see below) are used where solvent attack occurs with the white silicone rubber. The open-top cap and Teflon / Silicone septum combine to give the most inert closure with needle access.