Connect two pieces of capillary tubing with these Upchurch Scientific PEEK™ MicroTight Unions. The True ZDV Unions allow two pieces of tubing to connect directly to each other - using the included gauge plug to ensure proper alignment (also applies to MicroTight Adapters). Choose from our selection of MicroTight Tubing Sleeves to use with the true zero dead volume (ZDV) P-720 Union. The P-771 True ZDV Union allows direct connection of 1/32" OD tubing without sleeves. Our P-772 Union direct connects popular 360 µm OD capillary tubing without sleeves, adding only 5 nL of swept volume with its 0.006" (150 µm) thru-hole.