Why they would call the ST lätt that way is a mystery to me, since it does in no way resemble the original ST. I also found info suggesting this pack was intended for the flygvapnet or airforce.
The third one actually is a LK35, recently purchased by me as part of a package deal.
I'll do a multi-part review/presentation of the packs, starting with the original ST, then the ST lätt and finally the LK35. Too bad I do not have a LK70 to complete the list.....
Weight: 2,5 kgs
Material: Steel tubular frame. Canvas pack with some form of manmade fibre straps. Polyester?
Now the only thing that this backpack has in common with the others is that it is Swedish military surplus, has a frame and is green. Oh yeah... and it has about the same size as the ST lätt; 35 liters.
Other than that, a completely different pack yet again.
The model is a very straight forward design; a square frame, a square pack and the necessary straps. That's it. No bells, whistles or gimmicks.
The backpack consists of one large compartment and a smaller one in the back. Closing that compartment is done by the simple means of pulling a string and fastening it with that typical Swedish closure. The is one large top flap, covering the entire pack and this has a waterproof lining on the inside.
Pros: simple, straight forward construction that appears quite durable. Narrow frame and pack, which does not stick out. The flap covers the whole pack and is waterproof. The straps for the entrenchingtool are a nice bonus.