Vividia Ablescope VA-400 USB Rigid Borescope Endoscope with 180 Degree Articulating 8.5mm Diameter Probe https://www.amazon.com/dp/B00GY7C9ZW...N6YTJDCVZFTTAX
Iíve had this model for several years. Itís a high quality image and allows recording either photos or images in HD. They make a newer model where the whole shaft is flexible, however Iím very happy with this and itís ability to very quickly adjust views inside a cylinder from piston head to walls to both valves in seconds in high resolution.
Itís a fraction of the price of scopes from vendors like Snap On and does a much better job, IMO.