Measure before buying a strap kit
Record mattress and cuff measurements separately.
Record length, width and depth
A size label such as queen does not describe mattress depth. Measure the mattress and compare those numbers with the manufacturer’s published fit range. Ask the maker if the package only says universal.
Count the included parts
Connection points, loose clips and cuffs are different things. Check the parts list for each piece and note which ones are optional accessories. Use the instructions for that exact kit.
Check the cuffs separately
Look for a measured circumference range for each cuff, along with a description of the lining. See the cuff fit guide for how to read that measurement.