El cheapo pencil case from Daiso

In reply to:

https://www.fountainpennetwork.com/forum/topic/366099-any-pen-case-that-accommodates-pilot-parallels-or-a-guider-desk-pen/

I'm sure any number of similarly cheap and basic pencil cases from Target, The Reject Shop, dollar stores, etc. will accommodate a whole bunch of Pilot Parallel pens just fine, if you just want to have something in which to contain and carry them outside.