What's a good UV light for leak detection?

Seems the best uv light wavelength is 400NM to fluoresce UV dye, going below that is moving towards the invisible UV spectrum they use for UV curing of glues etc?

try this. i bought it a year back, works great especially if you got the woods glass along with it.

https://www.gearbest.com/led-flashlights/pp_277704.html

I’ve been using this combo at work for car A/C leak detection;

Convoy S2+

Lens filter

I built it myself from the same parts a few years ago, but it’s just too easy to buy it pre-made now!

Convoy S2+ with new copper board is not availiable in all shops as they got likely old stock
On the official Convoy shop you get 15% BLF discount and for sure new light
https://de.aliexpress.com/item/S2-black-UV-365nm-flashlight-nichia-365UV-in-side/32515105965.html

combined with an ZWB2 filter this light has almost no visible light output and about 600mW UV light output after optics

there are more lights with good UV LEDs
https://de.aliexpress.com/item/CountryMan-NSCU276A-3-Watt-schwarz-UV-365nm-f-hrte-taschenlampe-nichia-365UV-in-seite-OP-reflektor/32837945801.html

some even with stock filter
https://de.aliexpress.com/item/CountryMan-Seoulviosys-365nm-UV-flashligt-OP-reflektor-fluoreszenzmittel-erkennung/32838209569.html
https://de.aliexpress.com/item/Jaxman-U1-Nichia-UV-LED-LAMPS-365nm-18650-LED-flashlight/32601984060.html

Thanks for the replies, why is the ZWB2 filter for 365nm light necessary for a flashlight that is already spec'd for 365nm UV?

Why do most of these lights use 365nm when 400nm is supposed to be the optimal UV wavelength for dye detection purposes?

Copper board? With 700mA UV LED without thermal pad?

The UV lights always spec their peak wavelength and have a lot of their output at higher wavelength, the thing with 365nm LEDs they light up 400nm stuff as well but have almost no visible output especially with filter, so the contrast is increased a lot,
you can literally spot a leak from 3-4m distance with those 600-800mW 365nm UV output on those lights in a dark room
and on a room with normal ceiling light on you can easily spot a leak from 1m

The Nichia 279A has only 85°C Tj and a thermal resistance of 12.9K/W to solder point, the original convoy Board was aluminum with very small pads and 1Oz copper, so the thermal resistance of that board was very poor

many reports of damaged lights in German forum, also mine was damaged, after I switched to Djozz special copper board with 3OZ and very big pads and copper plane around them it did not deteriorate further

I understand this.
My question was - are you sure that Simon will provide UV Convoy with copper pcb?

New Convoy UV have improved copper board, the question is when other stores cleared old stock