FOOTSAK is a Footwear Self-Assessment Kit intended to empower people with diabetes by providing the necessary tools and instructional materials to enable self-assessment to determine whether footwear has adequate length and width. This feasibility study aims to determine whether people with diabetes and their footwear buddies can use FOOTSAK with sufficient (1) accuracy, (2) reliability and (3) ease of use to identify incorrectly fitting footwear (IFF).

Ten people with type 1 or 2 diabetes without any minor or major toe or foot amputation will be recruited to use the FOOTSAK. Given that foot measurements have to be made whilst standing (to ensure full blood flow to feet during measurements), ten 'Footwear buddies' - will also be recruited. These are people with or without diabetes willing to measure the feet of participating people with diabetes (for example, a spouse, partner, carer, friend, neighbour, or housemate).

Both participants are asked to watch instructional videos/short demonstrations and read large text instructions. Footwear buddies are asked to repeatedly measure the feet of people with diabetes. People with diabetes are asked to repeatedly measure their footwear then assess whether they are correctly fitting. The feet and footwear of participants with diabetes are then measured by a trained researcher to determine accuracy.

1. Determine whether foot measurements made by footwear buddies are accurate: +/- up to 5mm when compared to a trained researcher.
2. Determine whether repeated footwear and foot measurements made by participants are reliable: Intraclass Correlation Coefficient ≥0.83 for footwear length and ≥0.72 for footwear width (assuming a 15% decrease in reliability when compared to a trained researchers' scores).
3. Determine whether FOOTSAK measuring tools and instructional materials ease of use ≥7.0 /10.0 using Visual Analogue Score with free text comments. Any measuring tool failing to obtain a score of 7.0 or higher will be replaced in consultation with PPI participants and any instructional tool amended through PPI.

1. People with type 1 or type 2 diabetes; with or without neuropathy; with or without a history of ulceration who have not had a minor or major amputation;
2. 'Footwear buddies' who consist of people with or without diabetes who are willing to measure the feet of participating people with diabetes - for example, a spouse, partner, carer, friend, neighbour, or housemate.

Inclusion criteria for participant type (1)

1. people who self-report as having type 1 or type 2 diabetes;
2. aged 18 years or over
3. without minor or major amputation
4. Without significant foot deformity
5. Able to read and understand English
6. Willingness and capacity to participate in the study and to sign the informed consent form

Inclusion criteria for participant type (2)

1. Aged 18 or over
2. Willing to act as a 'footwear buddy' for a person with diabetes
3. Able to read and understand English
4. with a willingness and capacity to participate in the study and to sign the informed consent form

Exclusion criteria for participant type (1)

1. Does not self-report as having diabetes (either type 1 or 2)
2. Not aged 18 or over
3. Has minor or major amputation
4. Has significant foot deformity
5. Unable to read and understand English
6. Unwilling or lacking capacity to participate

Exclusion criteria for participant type (2)

1. Not aged 18 or over
2. Unwilling to act as a 'footwear buddy' for a person with diabetes
3. Unable to read and understand English
4. Unwilling or lacking capacity to participate in the study