If you calibrate a high number of transmitters in a week, you definitely want to conserve your nitrogen. Especially when you're so far out in the field that driving back to the shop isn't an option. Blowing off 100' of nitrogen in the test hose adds up over time.

With the addition of a few fittings, you can conserve the nitrogen in your hose between tests.

Note: The following diagrams show common examples of ways technicians kit out their hose reel to control nitrogen loss and perform calibrations. Not all items listed will necessarily fit your specific setup.

Regulator for your nitrogen bottle 
XREG Pressure Regulator - Single-stage pressure reducing regulator for use in providing a stable pressure to precision pressure control devices.

Block and Bleed Valve 
QTHA-BLB0-HC -  Seal and control the outlet side of your hose.

Test Manifold 
QTCM - Fine-adjust your test pressure right at the transmitter. Mount your calibration gauge to the top so you can see the readings as you fine-adjust.

Short (5 feet) Quick-test hose 
QTQT-HOS-5ft - 5 feet of hose to connect your nitrogen regulator to the hose reel, the block and bleed valve to the test manifold, and the test manifold to the transmitter. 

Fitting to tie in to the transmitter manifold 
QTFT-4MBO - Easily connect a Quick-test hose to the transmitter for calibration. Easily sealed bubble-tight again when calibration is complete. Many pipeline organizations install the QTFT-4MBO on all transmitter manifolds by default to speed up test setups and after-test cleanup.

1/4" female NPT Quick-connect x female Quicktest fitting 
QTHA-2FSA-QD - Use this to connect your reference gauge to the QTCM test manifold.