Ports and fittings


Ports and fittings are the inlets and outlets of our flow instruments. As with many threading and connecting designs, needs vary by mechanics and standards. Higher flow, higher pressure applications need more robust threads to withstand the forces involved, and the converse is true too.


For Alicat devices, the default type is NPT (National Pipe Thread). Other types of threading or connecting are options. We carry a lot of options, including SAE, AN 37 degree Flare, welded VCR, welded VCO, Swagelok compression and BSPP (or “G”) fittings, threads and port sizes. Below are the options we carry tooling for in our own manufacturing facility. Your choices are greater than these, because we can always have exceptions manufactured outside.


Ports and fittings with threads need to be machined into instruments when the order is placed. With the exception of some after-market adapters, ports and fittings cannot be changed in the field—then only to restrict flow, not to increase it.
Speak with your Alicat representative to review your options before placing your order.


Available NPT female process ports for Alicat devices

NPT SizeM SeriesWhisper
1/8”100 SCCM – 20 SLPM50 SCCM – 5 SLPM
1/4″50-100 SLPM10-20 SLPM
1/2″250 SLPM40 SLPM
3/4″500-2000 SLPM50-500 SLPM
1-1/4”3000 SLPM
2”4000-5000 SLPM1000 SLPM

*Flow rates below 100 SCCM for M series use M5. Flow rates below 20 SCCM for Whisper use M5.

Available SAE sizes for Alicat devices.

Dash SizeO-Ring ThreadProcess Boss Port SizeAlicat M Series
M5 (10-32 UNF)0.5-10 SCCM
25/16-241/8”10-50 SCCM
47/16-201/4”100 SCCM–10 SLPM
69/16-183/8”20-100 SLPM
83/4-161/2”250 SLPM
107/8-145/8”500-1000 SLPM
121-1/16-123/4″1500-2000 SLPM
161-5/16-121”3000 SLPM
24*1-7/8-121-1/2”4000-5000 SLPM

*The port tool for this option is not available in our shop at this time.

Available AN 37° flare ports for Alicat devices

Dash SizeO-Ring ThreadProcess Boss Port SizeAlicat M Series
69/16-183/8”20-100 SLPM
83/4-161/2”250 SLPM

Available welded VCR fittings for Alicat devices

VCR Size and GenderM Series
1/8” welded VCR female0.5-50 SCCM
1/4” welded VCR male100 SCCM-100 SLPM
1/2″ welded VCR male50-250 SLPM
1” welded VCR male500-3000 SLPM

*More sizes and other gender options available upon request

Available welded VCO fittings for Alicat devices

VCO SizeM Series
1/8” welded VCO0.5-50 SCCM
1/4″ welded VCO100 SCCM-100 SLPM
1” welded VCO500-3000 SLPM

*More size options available upon request

Available welded Swagelok compression fittings for Alicat devices

VCO SizeM Series
1/4″ welded compression100 SCCM-100 SLPM
3/8” welded compression50-250 SLPM
1/2″ welded compression50-500 SLPM

*More size options available upon request

Available BSPP “G” process ports

BSPP SizeM Series
1/8”100 SCCM-20 SLPM
1/4”50-100 SLPM
3/8”50-250 SLPM
1/2”250 SLPM
3/4”500-2000 SLPM


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