I have the Harbor Freight HD model. This is the more expensive one; goes on sale for under $200 periodically. It has a nice, slender probe that goes into spark plug holes, behind timing elt covers, into rifle bores (over about .35 cal.) into computer cases and suspension systems to read part #'s, etc. The cheaper, $69 version doesn't have the camera resolution or slender enough probe to make it useful ,IMO