Tube Holder Kit, Dual Variable Manifold (Includes Back Catalog number: 800251 Manufacturer: SENSIDYNE Availability: In the manufacturer's stock Price on request - + Recommended 811-9981-50 Sorbent Tube, Porapak-N, 6X70, 88/44, 50/BX Price on request 811-9978-20 Sorbent Tube, XAD-2, 8X110, 450/225, 20/BX Price on request 811-9975-50 Sorbent Tube, XAD-2, 8X110, 400/200, 50/BX Price on request