The bin liner gauge is the thickness of the bag itself. Gauge is the measurement of the thickness of standard low-density plastic bags. It is related to the SI measurement of microns as 1 micron = 4 gauge. The typical gauge sizes and microns equivalent are:

100 gauge = 25 microns = Light Duty, economy black bin liner typically sold in discount stores.
120 gauge = 30 microns = Medium duty, this would be the standard bin liner.
140 gauge = 40 microns = Medium Duty, the most popular thickness bag for refuse sacks.
160 gauge = 40 microns = Extra Medium Duty for General purpose, strong quality black bin liner for domestic use.
200 gauge = 50 microns = Heavy duty bag, suitable for commercial waste.
300 gauge = 75 microns = Extra Heavy-duty, ideal for building & garden waste.
500 gauge = 125 microns = Normally a rubble sack for building waste.

Regardless of the thickness of the bag, sharp objects such as glass and metal will puncture or tear most bags. Thin bags will tear or puncture by pure weight, however, thicker bags will not tear easily without first being torn or punctured. Some bags will be made from medium or high-density polyethene. This most certainly makes them more wrinkled (like the typical supermarket bags you will find) and can be made thinner for the same strength.