This part is a perfect fit on my Webasto Airtop 2000 STC Gasoline heater. I installed my heater under the passenger seat of my ProMaster Van. It was a tight fit so this elbow allowed me to duct the hot air where I needed it to go to the back of my van. Easy to use. I made the RIGHT choice! Thanks VMACS for shipping this cross country. Be safe out there people.