The CRL FW623L Mercedes Sprinter 170″ Rear Quarter Dual-Vent Window has a Two T-Handle to open the bottom vent glasses like a canopy to allow air flow, the Vent features a detachable screen. (both bottom panels open). If you accidentally brake one or both of the openable glass windows, you can order replacements here.
CRL VENT623LF Front Vent Glass Replacement for FW623L Mercedes Sprinter 170″ Rear Quarter Dual-Vent Window (Driver Side)
CRL VENT623LB Rear Vent Glass Replacement for FW623L Mercedes Sprinter 170″ Rear Quarter Dual-Vent Window (Driver Side)