The M553 was the recovery variant (wrecker) within the Caterpillar GOER family. This truck was very capable cross-country, but perhaps less effective on road moves, where its tyre-only suspension and quirky steering caused drivers to limit its speed to less than 35mph. The wrecker was designed to recover other GOERs or smaller vehicles, and was fitted with a crane and powerful winch. Further information can be found at https://en.wikipedia.org/wiki/M520_Goer and http://www.acmoc.org/bb/showthread.php?12060-Caterpillar-GOER-M553-Military-Wecker, which provides further links.
The model is based on the standard front unit, with a dedicated and larger cargo unit. These are provided as separate parts, with a link bar that can be glued in position, or mounted with a pin and the second coupling part to provide limited articulation (somewhat fiddly to assemble, unfortunately). The crane is a separate part that fits on to the supports as shown. A separate windscreen assembly, that can be glazed with transparent plastic sheet, is also included. Two extra tyres should be printed and mounted in the cargo area as shown to complete an impressive model at this scale.
The product is offered for personal, non-commercial use under the Attribution-NonCommercial 4.0 International (CC BY-NC 4.0).