Tube Holder Adapter, 3/16" to 1/4" Ends Back Catalog number: 200187 Manufacturer: SENSIDYNE Availability: In the manufacturer's stock Price on request - + Recommended 811-9983-50 Sorbent Tube, Porapak-Q 6X110, 150/75, 50/BX Price on request 800071 Tube Holder Housing End, 5/8", for 1/4" OD, Open E Price on request 811-9981-50 Sorbent Tube, Porapak-N, 6X70, 88/44, 50/BX Price on request