This Kurgo Dog Harness is part of their leading Tru-Fit range.
Marketed as the CAMERA MOUNT edition it integrates two small fixing plates (chest and back) to attach devices such as a GoPro but even if this isn't important to you this will act as a sturdy everyday harness at a bargain price.
S - Neck 30-50cm / Chest 41-56cm / Weight 5-11Kg
M - Neck 40-63cm / Chest 46-71cm / Weight 11-23kg
XL - Neck 61-89cm / Chest 71-112cm / 36-50Kg