A martingale collar is made with two loops. The larger loop is slipped onto the dogs neck and a leash is then clipped to the smaller loop. When the dog tries to pull, the tension on the leash pulls the small loop taut, which makes the large loop smaller and tighter on the neck, thus preventing escape.Properly fitted, the collar will be comfortably loose when not in use.
To measure your dog for a Martingale Collar, use a soft tape measure or a piece of string and take the measurements at point A, B, and C in the drawing below.  Choose the size that fits within this range to ensure that your collar fits perfectly.
 
For Sighthounds, the measurement at points A and B may be the same or very similar, this is because their heads are often the same size or smaller than their necks.  For non-sighthounds, these measurements will be different and you will need to choose a collar size that is large enough to slip over the head (point A) but not too large to fit correctly at point B.
 
In other words, choose the smallest size that will still fit your dog.  If your dog has a 39cm neck(C), a 42cm ear(B) choose the 35-45cm,which is 45cm including the martingale section but when pulled, will tighten to 35cm (or smaller if adjusted) or the  40-50cm, which will need adjusting down quite a lot. The slides on the collar should not meet when pulled or the dog may still slip their collar. 
 
Buying Guide;
To ensure you order the correct size Martingale Collar, please use this guide.
 
The Martingale loop makes up approximately 10cm of the 2cm & 2.5cm Collars, and 13cm on the 4cm & 5cm Collars, so a 2cm wide 40cm Martingale will be approximately 30cm when pulled, but 40cm when laying at rest. Each Collar has an adjustment slide so it can be made smaller.
In this instance, if your dogs head and neck are larger than 30cm, but smaller than 40cm, this should fit. If your dogs neck is smaller than 30cm, they will most likely be able to slip out of this size so you would either need to order down a size or adjust the collar to be smaller with the adjustment slide.
1. Select the collar width and design you like
 
2. In the Collar Style & Hardware Options – Select “Martingale with Solid Brass fittings” OR “Martingale with metal & Stainless Steel D-Ring”
 
3. Using the measurements above select the size/ length that is the closest to your largest measurement but not smaller
 
The Size in the order drop down menu are indicated below in Bold. This is the length of the collar at rest/ its longest setting. Collars can be reduced in size by utilising the adjustment slide. If in doubt, please do not hesitate in contacting us.
 
Remember that using the measurements taken as per above, you are looking for a collar that allows it to slip over Point A (indicated by Bold Text in the first row)
Point B should be slightly larger than the size the collar will tighten to, and Point C is where the collar will sit on your dogs neck so should measure between A & B
 
2cm & 2.5cm Collars
30cm=On largest setting, when pulled will tighten to 20cm without moving slide adjustment
35cm=On largest setting, when pulled will tighten to 25cm without moving slide adjustment
40cm=On largest setting, when pulled will tighten to 30cm without moving slide adjustment
 
 
4cm & 5cm Collars
35cm=On largest setting, when pulled will tighten to 20cm without moving slide adjustment
40cm=On largest setting, when pulled will tighten to 25cm without moving slide adjustment
45cm=On largest setting, when pulled will tighten to 30cmwithout moving slide adjustment
50cm=On largest setting, when pulled will tighten to 35cm without moving slide adjustment
55cm=On largest setting, when pulled will tighten to 40cm without moving slide adjustment
60cm=On largest setting, when pulled will tighten to 45cm without moving slide adjustment
65cm=On largest setting, when pulled will tighten to 50cm without moving slide adjustment
70cm=On largest setting, when pulled will tighten to 55cm without moving slide adjustment