The daypacks come in one backlength. The larger daypacks have adjustable backlength and the largest daypacks have two shoulder strap sizes. All the daypacks have sewn in hipbelts in one size to fit all body sizes.

The larger models are available over the range of three backlengths, S, M and L. The table below shows which backlengths are available for each model. To determine which size is best, you need to determine your backlength: the distance from the top of your hip bones to the mid- point of your shoulder (where the shoulder strap goes over the shoulder). One way to do this accurately is to stand with your back against a wall with a hard cover book and pencil in hand. Place the book vertically against your side with the bottom edge of the book resting on top of your hipbone and the back edge against the wall. Mark the height of the lower edge of the book on the wall. This is the height of the top of your hips. Now place the book vertically by the side of your head, with the back edge resting against the wall and the bottom edge resting on the mid-point of one shoulder (half way between your neck and the end of your shoulder - this is where the center of the shoulder straps should lie). Mark the height of the bottom edge of the book on the wall. This is the height of your shoulders. Now measure the difference in height between the 2 marks on the wall - this is your backlength. Make a note of this.

Below there is a chart, under the heading "What Volume Do I Need?". The top light blue section lists the various back lengths in centimetres and inches so you can find your back length there. The vertical left hand margin shows various pack volumes. By choosing your correct back length and the volume you require, you will find the appropriate models.

If you want to know what model we recommend, we need to know:

1. Whether you need a long or a short backlength.

2. The maximum volume you need (in litres).

3. The type of activities you are doing eg. hiking/ tramping, mountaineering, running, biking etc.

4. The type of country eg. rough, scrub bashing etc (you need a Stronglite); tracks and open country (an Ultralite is good).

The volume of pack needed by different people for a certain length of trip varies considerably between individuals depending on gear choice and is also affected by the season and the terrain. Packing your gear in a pack of known volume is a good way to determine your volume requirements. Note that the Ultralite family includes the Balance Pockets as standard, therefore the specified volume is with the Balance Pockets.

With the Stronglites , the volume specified is only for the pack itself, so adding your choice of Balance Pockets or Bags will increase the total volume accordingly. Therefore you need to add the volume of the Balance Pockets or Balance Bags to the volume of the pack to get the total volume to match your requirements.

Now consider the longest trip you will do with the pack and the gear required. This will determine the volume of pack needed. Now think about the predominant use and choose the most appropriate family for your needs.

NOTE: We strongly recommend using Balance Pockets or Balance Bags in all situations except technical climbing. They will reduce energy use and body pain compared to carrying all your load behind in a backpack. The instant gear access of the pockets also increases efficiency, as you do not have to stop and take the pack off to access items needed during the day. Specific purpose Balance Pockets, Bags and clip-on accessories allow you to customise your pack for different activities.

Based on your backlength and the volume you require, you can see in the chart below what models will work for you. To further refine your selection, you need to take into account your activity and the sort of country you will be using the gear in.