Zero branded Tuovt TD-8008 (which replaces the HOTA A-3051 shown in last product image)
Internal diameter 134mm (~5.27 inches). Width at bead: 42mm (50mm on the HT-017).
Notes:
Typically accompanied with 50-134 tubes, such as the ULIP 8½x2" (50-134) or similar sized CST 8.5x2.00-5.5. A specific compatible tube is produced (L-7) however it is only offered in 45 degree - will be added to catalogue if assessment finds it to be suitable.
First product images show the TD-8008, the HT-017 with the last being an image of the former HOTA A-3051.