I have been using a Fenix LD02 and find it close to perfect but with just a few quirks that keep it at good instead of perfect. The clip is a bit weak looking as it bends like it is close to coming off but so far hasn't. The exposed clicky tailcap switch is nice and easy to use but is unprotected so occasionally gets turned on accidentally and runs the battery down if I don't notice it. Lastly the default and as far as I can tell only set up starts with the medium level and switches to low then high. I would prefer a light with either 2 settings and starts on high or even only a high setting. Starting on high with the initial click is the key. With the background and complaints listed I am looking for a single AA or single AAA with tailcap clicky or reverse clicky switch where the switch is protected by a metal surround. The light should have a clip to clip to a pocket but if all else is there have the ability to have a good strong clip mounted to it. 1,2 or 3 modes are fine but starting on highest mode on initial click is most important. Lastly I really like how small the LD02 is for both diameter and length. It could be a few mm larger dia and maybe 10-15mm longer in length. Budget is around $45 or less but if it is perfect I will go a bit higher. I like black anodized aluminum but stainless steel or Ti are also good and if a polymer could meet the size factor it would be OK as well. The light is used as a primary EDC clipped to weak side (left) pocket for emergency and tactical in a pinch use. I almost forgot LED but I assumed the form and size dictated LED. 80+ lumens or so for high setting. I appreciate the informed masses opinions and suggestions.