Joe's correct Jen. For your
Burro (or most any 13', or even 16/17') the lightweight BAL jacks will be perfectly adequate. The 17" 23025 models will do for most older trailers unless they've been modified with larger wheels/tires or a higher
axle mount. Even then, use of the 'stacking blocks' or a board will usually allow them to work OK. I've noticed some folks have had a problem with jacks or other items 'slipping' off of wet boards. Guess I've been fortunate, in more'n 50yrs of camping & using wood boards for leveling & other support I've never had that happen. I'm usually able to level my camper pretty well without using any additional support but not always. In any case, the 20" model 23026 will provide good support for taller campers. If you have one of the larger, heavier 'eggs' the 'C' series BAL jacks will serve admirably, & they work/operate just like the lightweight models & can also be used as levelers, tho unless mounted & used judiciously, they can 'rack' your trailer chassis which may cause other alignment problems.
The Atwood style jacks are also pretty good & have been used for many years on camp trailers, especially pop-up types. I've had 'em on several different rigs & they've always worked well when deployed & 'set-up' correctly. I've now gotten to the age where it's lots easier for me to lean over slightly & 'crank' down the BAL jacks rather than getting on my knees to deploy the Atwood style.
I'm currently working on fabricating a 'slotted' socket for the BAL screw lift that'll fit in my DeWalt cordless drill to make lowering the BALs a little easier.