Stall strips are usually wedges fitted to the leading edge of the wing which are designed to deliberately break up airflow, inducing a stall at high angle of attack.

The typical layout would be to fit them at the wingroots, to provoke the stall to develop at the wingroots rather than the tips thus, hopefully, giving a more predictable stall.

I have never tried them on a model and it would be interesting to see how they perform.

I have a sneaky feeling though that they'd be more trouble than they're worth on a model. They need to be positioned on the leading edge in such a way that they provoke the stall at a useful angle of attack. Fitted too high up the leading edge, they'll have the affected wing area stalled far too soon, reducing your lift and offering you little advantage. Too low on the leading edge and you'll still manage to stall asymmetrically before the breakers do anything at all.

My personal feeling is that washout is a more predictable and effective technique for our purposes, although including washout into an ARF wing is easier said than done...