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.
All the larger models come in 3 sizes, S, M and L. (To see which sizes are available in a particular model, consult the table below). 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 covered 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.
The large models with Pelvic-Form Hipbelts have 3 hipbelt sizes. The medium size, M is standard. To decide whether this will fit, or whether you need a S or L size, use a tape measure to determine your waist size, as the top of the hip belt goes around your waist. If this distance is less than 85 cm choose the S size, if it is greater than 95 cm, choose the L size. Between 85 cm and 95 cm, choose the M size.