Four members of a legislative panel are spending a few days in Colorado on a mission to learn the ins and outs of marijuana regulation.

Recreational marijuana is already legal in Maine thanks to a voter-approved referendum last fall. But a joint legislative committee is tasked with figuring out the nitty gritty of implementing sales of retail marijuana.

The committee is set to soon vote on specifics like a likely tax increase on recreational marijuana.

Democratic Rep. Teresa Pierce says there’s advantages to seeing retail shops and talking to state officials in person.

Republican Sen. Roger Katz told the Portland Press Herald the trip could prompt tweaks though not huge changes.

The trip’s cost isn’t yet known.

The lawmakers will return in time for the Legislature’s last official day Wednesday.