The ABEC rating is the higher the number the higher the precision. For very high speed (20-30,000 rpm) air floated bearings ABEC 9 is appropriate, or maybe for precision measuring equipment. The opposite end will be used for skate board trucks. The tiny wheels hammer over gravel and if the ABEC rating used was any higher than 1, it would end up as 1 after a few days (if that long)
I would recommend "Blue Seal" bearings from Trail Vision. They have max fill marine grease, strong double rubber seals, and ABEC 2 -Grade 10 balls.
Trailvision - Bicycle Specific Bearings Have a good look around they do sets for some bikes and they have lots of info on the bearings so that you can be sure to get the right ones.
Here is something in my files that found about
Enduro bearings. It was created in 2015 and I can't remember whether I wrote it or copied it from somewhere. Interesting.

Hmm, I just spotted the mis-spelling of "complement". So I must have copied it!
Enduro Bearings
Enduro bearings supply product solely to the bicycle trade. They source from the same manufacturers as other industries, but they claim to optimise their kits to provide the best bearing type, seal type and grease for a given application.
As an example, let's take the 6902 bearing they recommend for some MTB main pivots.
It's a full compliment or "max" type bearing with more balls per race than a "regular" castellated type and in theory, it should handle higher loads. They add a mid to high contact labyrinth seal that runs in a specially machined channel to keep the dirt out (LLU) and the CRC staplex waterproof high pressure marine grade grease that won't dissolve and wash out, even in salt water and jetwash conditions. So their bearing of choice for this application is a MAX6902LLU and they sell for about £8 - £10each.
Sounds fantastic doesn't it?
In reality though, they're no better than average 6902 2RS that you can get online for about 20p each because the grade of ball and manufacturing tolerance of the bearing is no better.
Enduro quote ABEC 3 and a ball grade of 10 (millionths off perfectly spherical) as their minimum standard. This is only one grade away from the worst quality bearings producers will put out for sale.
SKF, FAG, INA etc. Don't even bother putting ABEC ratings on their products that I can find. I guess they just use the best quality materials and processes as their minimum standard. Which is probably why they last longer and work better.