Wall heater for 2”x3” stud interior wall?

[Sean Hoffman]

Hey there- I’m getting a rental ready for market and two bedrooms have no heat source so I’d like to install Cadet style in-wall heaters. The main living space and master bedroom are served by a Ductless.

The issue is this is a cheaply built 1960s house and uses 2” x 3” interior stud walls. Has anyone found a good quality heater for this space? Most everything I’ve looked at is for 2” x 4” walls. Thanks!