Gary, if you have the horizontal sliding windows, Max Air also makes a vent for these windows so you can leave them cracked open for ventilation. If you are needing to secure the window, you can cut a dowel (sp?) or use a 1" X 1" the length of space between the partially open window and the window frame to restrict as to how far the window can be opend and place it on the bottom track window would slide in.
Mike, RVIA & RVSA Certified Master RV Technician
Amy, Dr. Assistant - Roxie & Mei Ling, four legs each
2000 Gulf Stream Scenic Cruiser 450 hp & 1330# torque
06 Saturn Vue, 06 Chevy Z71 4x4 & 2014 Corvette Z51 M7