At 1530g, the Thunder 50 is light, but not at the expense of  useful, and clever, features.

The most innovative feature is its T-Rex suspension system – a T-shaped aluminium alloy stay with separate lumbar and shoulder pads mounted onto it. The pads are attached to the stay by single anchor points, so they can pivot from side to side as you move.

The fully adjustable suspension system is among the most foolproof I’ve come across. The curved stay distributes the pack’s weight squarely onto the hips, and has the added advantage of holding the pack off the back, which helps minimise sweating.

The ‘dual-density’ foam hip-belt combines denser and more rigid foam on the outside for load bearing with softer foam on the inside. I found it comfortable, even with a pack weight north of 20kg.

I was impressed by the harness, but I found the lumbar pad bulky and it may not suit all back types.

In addition to the single compartment, extendable chimney and floating lid, the pack has five mesh pockets for stowing gear. The main compartment can be accessed through two side zippers.

Exped has abandoned buckle clips in favour of metal ‘rapide’ hooks to attach the compression straps and the lid. They are solid and durable, though a little fiddly to use. When the pack is not completely full, the lid can be clipped anywhere on the vertical daisy chains running down the front of the pack.

Other features include ice axe loops, with incisions for inserting trekking poles.

The Thunder 50 is a comfortable trekking and alpine pack for short multi-day trips. It’s a good choice for those looking for a light pack that remains comfortable with a heavy load.