Amazon.com : IFOOTAGE Phone Tripod Mount/Smartphone Tripod Adapter with 38mm /50mm Base Plate Adapter/Phone Holder for Tripod Video Live Stream Vlog Selfie-Red : Electronics
Durable Tweeter Horn Converter for Head 50mm to 38mm,38mm to 26mm Throat Treble Horn Adapter Treble Audio Accessories - Walmart.com
PVC 38 mm hose connector 50 mm adapter pool hose nipple
SVBONY SV186 T2 Camera Photo Adapter Plug Telescope Eyepiece OD 38/45.8/50mm | eBay
Amazon.com : IFOOTAGE Phone Tripod Mount/Smartphone Tripod Adapter with 38mm /50mm Base Plate Adapter/Phone Holder for Tripod Video Live Stream Vlog Selfie-Black : Electronics
Vacuum Cleaner Thread Hose Connector/adapter/connect Brush And Hose,inner 38mm,for Thread Hose 32mm/39mm,vacuum Cleaner Parts - Vacuum Cleaner Parts - AliExpress