German tanks and vehicles used to have hooks to lift heavy parts like engine cover or the whole turret.

While intended to stand heavy weights, these were not armoured parts and therefore had a moderate thickness.

Usually, photoetch parts have replaced them, however a problem of the photoetch is that its thickness is consistent for all parts, neglecting the differences of real pieces. Moreover, the process to build them only allows for two "levels", without fully three-dimensional parts.

The 3D printing process overcomes these problems, allowing any thickness and shape, as it is shown here on a variety of hooks from T-Rex Studios.

There are three different sets, and each one has also variants of the hooks.

The product is 3D printed, not a resin copy of a 3D  master. Inside the cardboard box, they come protected by a rigid plastic box, with padding foam inside. 

All parts of the three sets are quite easy to remove from the carrier, I had no problem cutting the base flat with a single edge nipper. There is no other operation required, assembling or cleaning -only attaching the part to the tank.

Printing quality is excellent, I have attached some photos from TRex website because they are much clearer than what I can do, but the parts I got are exactly the same. There are no visible steps or deformations, and holes go all the way through on all parts. The material is slightly soft, not being so fragile and prone to break as other types of resin. This is definitively a plus for cutting and manipulation.

Let's see each set.

First is TRex reference 35026, 1/35 Lifting Hook for WWII German Panzer Set A. This is a set with three types of hooks valid for StuG III and IV, Hummel, Nashorn, Panther and variants, Konigstiger or Jagdtiger.

The shape looks correct, and Panther hook has the correct (tiny) hole as you can expect.

These hooks can be found on the engine deck or driver's compartment roof of aforementioned vehicles, here are some examples from museums:

Second is reference 35027, with two types of hooks for PzKpfw I and PzKpfw II. Again some tiny parts, perfectly reproducing the real hooks.

Included also for reference some real photos.

The last set of hooks is reference 35028, thee types then can be used for PzKpfw III and PzKpfw IV.

Types A and B are quite similar except for one using bolts and the other using conical heads. Using only the naked eye, it is difficult to see the difference, but it is there for the photos. Even more, the bolts correctly reproduce the castle type.

Conclusion

These sets are absolutely recommendable to replace plastic parts, offering much better quality with correct shapes and thickness. Also, using them is straighforward as it is only needed to remove them from the base.