Milk bottles before the 1930s were round in shape. In 1935 slender-neck bottles were introduced in the UK. In the 1940s, a square squat bottle became the more popular style. Milk bottles since the 1930s have used pyroglaze or ACL (Applied Color Label) to identify the bottles. Before the 1930s, names were embossed on milk bottles using a slug plate. The name was impressed on the slug plate, then the plate was inserted into the mold used to make the bottle – the result was the embossed name on the bottle. In 1980 a new bottle, nicknamed "dumpy," was introduced in the UK where it remains the standard now.