strongtools 3.9mm small hole borescope, aperture endoscope camera - suitable for. 20 caliber and larger pipes, gun barrel inspection tool, suitable for android and ios smartphones iphone, ipad, samsung is up for auction in Industrial & Scientific. The current bid is $1.00, 97% below the $35.99 MSRP, in As Is condition. This auction has ended — similar items appear in live auctions regularly.