Teslong Two-Way Articulating Borescope, 5.5mm Slim Probe, 5.0'' Industrial Endoscope with Light, 5FT Flexible Snake Scope for Automotive, HVAC & Mechanics

This one!

We went with this one. There are some out there that are way cheaper, but this brand had good reviews and this one felt like a good balance of reasonable price paired with a slightly slimmer than normal scope. Edit - something to keep in mind, it’s got a little cap on the end of the scope to protect it. You have to take it off for the picture to come through. Maybe obvious to other people, but I had a few minutes of “oh no it’s defective!!!” before I realized.