These Metal Pet Tags are from UniSub. They are available in 3 different sizes and are printable on one side which is a rather bright white. Being UniSub the sublimated image transfer is fantastic.
Overall measurements of these are shown below and they are made of aluminium hence making them light to fit onto pet collars but robust enough to withstand day to day wear and tear. They also come complete with a clip to fix to any animal collar.
Shapes available are:
US5571 Bone: 38mm x 25mm x 1mm
US5573 Circle: 32mm x 38mm x 1mm
US5573 Heart: 32mm x 35mm x 1mm
If you want an alternative pet tag product of the same style but in a plastic double sided version please click this link.