Your search for "CSRK-TA-WB-LE-BB-SW4B" revealed the following:

How to Measure Trailer Leaf Springs — and Know What Else Needs Replacing

A trailer leaf spring can look “close enough” and still be the wrong replacement. Correct fitment depends on more than axle capacity. You need to identify the spring style, free length, width, leaf count, capacity, eye/bushing size, and the suspension hardware around it. Measure the suspension before ordering — and...