Tools & Fabrication - What’s a good A/c leak detector sniffing tool?

What’s a good A/c leak detector sniffing tool? The issue is this, my 99 fbody has consumed 1 can of R134a in the two years I have owned it, I do not know if it has ever had any additional Rr134a added since 99 other than the can I added but my gut feeling is, I do have a slow leak. So since my car is a garage queen, its kind of a hassel to bring the car to a shop and get it diagnosed since I work out of town so I was going to buy one of these to add to my tool box since it seems most older cars have a/c leaks. I noticed the cheaper ones on eBay run around $50 (made in china) and up and you can find used snap on, matco, mac, and bluepoint for around $75 and up. So, I am looking for the probe type with the long neck, not the uv checker, Any suggestions?