I have 2 of these Briggs otoscopes: http://www.amazon.com/Briggs-Stratton-1 ... B00DJR1IDO Frankly, they're junk. I have a mobile business, so granted, they take a bit of a beating just riding around in truck, but so does the rest of my equipment. The bulbs alway blow out and sometimes I have to hold the button down so that the light says lit.
I just bought one of these: http://www.drmomotoscope.com It has LED bulb, so I'm hoping for a longer life. I'll report back on that when I give it some use. It has a more solid feel to it, is all I can say now.
Incidentally, either one is priceless when it come to finding junk in carbs. Instead of assembling and installing only find out that there's still junk in the carb, many times you can see it with the scope. I use it before reassembling any carb.
While I'm at it, I wanted to mention this flashlight: https://www.nebotools.com/prod_details.php?id=293 I'm behind the curve when it comes to using LED flashlights, as this is my first one. But, I mean, it'll hurt your eyes if it happens to be pointed at them when you turn it on! Again, I use it on my truck. If you've ever tried to use a conventional flashlight in the sunlight, you know it doesn't "get in the cracks" like you need it to. This LED light does so easily. I do a lot of work on the ground behind my truck and the sun can actually make it tougher to see in tight areas.