Our other sites:

What pole sander sizes are available?

Shop for Manual Sanders

Sizes of pole sanders The size of a pole sander can vary, depending on the individual model and manufacturer, in addition to the type of sander head being used.

Handle 

Handle length Pole sander handles are available in a range of different lengths. A user can choose from one as short as 400mm (16″ approx.), or one as long as 3m (118″ approx.).
Pole sander handle length Telescopic handles can extend or shorten to suit the task in hand. Handles with this feature can usually shorten to 400mm (16″ approx.) and then extend anything up to 1300mm (51″ approx.).

Sander head

Cut the sandpaper to fit the size of the sander head It is important to know the size of the sander head, in order to cut the piece of sandpaper to the correct dimensions.
Rectangular sander head is measured in length x width

Rectangular

A rectangular sander head is generally 80mm (3″ approx.) in width by 230mm (9″ approx.) in length, although this can be slightly different on various models.

Most models of rectangular sander head will accept a 1/3 sheet If a user does not wish to cut sandpaper to size themselves, some rectangular sander heads will accept pre-cut sheets, which will save time as they are already the correct size.
Circular sander head diameter

Circular

A circular sander head is usually 230mm (9″ approx.) in diameter.

Pre-cut sheets of sandpaper are available Pre-cut circular sandpaper sheets are also available for circular sander heads. These sheets are ideal, as the user does not have to waste excess sandpaper by cutting a square piece into a circular shape. They are commonly attached to the sander head via a hook and loop design, meaning there is no need for additional length to wrap around the edges.
Triangular sander head measured in length

Triangular

A triangular sander head can vary in size slightly, however, it is usually equilateral at around 240mm (9.5″ approx.) in length on each side.

 Donkee says 'Equilateral means a triangle which has three equal sides
Pre-cut pieces of triangular sandpaper are available Similarly to the other types of sander head, pre-cut sheets of sandpaper are available to fit most models of the triangular shape. As with the circular sandpaper sheets, they are usually attached to the sander head by a hook and loop design.