From back when Schwinn wasn't such a dirty word. 19" - 1998 Mesa GSX frame, Surly 1x1 fork, headset and generic stem.
This bike was just below the Moab line. Super solid, room for some pretty fat tires. Frame is rim brake only, but there is a disk tab on the fork. Paint has some scratches but no dents. Overall, it's in great shape.
If you're interested I'll also include the original fork - Rock Shox Indy S. It works great....for a 15 year old elastomer fork.BikePedia
Edit for frame size - it's 19".