4 inputs determine the right manual & shutoff valve.

A distributor-facing pre-quote checklist. If the customer answers most of these at the first call, the second call is the quote.

1. 01
   What's being isolated, and where does the valve sit on the line?

   Sets which manual valve fits the job. Machine drop or branch take-off → quarter-turn shutoff upstream of the FRL so the bowl, regulator, and tooling can be serviced without bleeding the branch. General line on/off → ball valve. Local point-of-use hand control → hand valve. The plant walk-through audit usually surfaces 10-50 drops and take-offs missing a shutoff.
2. 02
   Does this location require OSHA lockout-tagout?

   The lockout requirement is what separates a shutoff from a plain ball or hand valve. If maintenance has to isolate and lock the branch for service, the valve needs a padlock-through-lever — that's the quarter-turn shutoff. Confirm the lever accepts the customer's lockout hardware. Where lockout isn't required, a ball or hand valve covers the manual on/off without the LOTO premium.
3. 03
   What's the port size and connection — NPT, BSPP, or push-to-connect ends?

   Branch take-offs from a header run larger (1-1/4"+); machine drops and point-of-use isolation sit in the 1/8"–1" range. NPT and BSPP are not interchangeable — match the existing line thread, or spec push-to-connect ends where the run is tubed rather than piped. Read the existing fitting or photo the connection before quoting.
4. 04
   What's the install environment — and is manual or lockable operation needed?

   Material is the spec that bites. Brass for general industrial air; bronze for higher pressure; stainless for washdown, food, pharma, corrosive, or outdoor service — brass into a washdown environment fails on a 6-12 month corrosion cycle and the price delta to stainless is modest. Pair the material call with the operation call: lockable lever (shutoff) vs. plain manual (ball / hand valve).