The numbers and stamps on lawn bowls identify the bowl's size, matched set, manufacturer or tester and official testing status. The rings also help you find the bias side—the side toward which the bowl curves as it slows.

Size number

The size is usually marked with a number. It relates to the bowl's dimensions, but the same nominal size can feel different across models and grips. Comfort and control matter more than choosing the largest bowl you can hold.

Serial number

Every bowl in a competitive matched set should carry the same serial number. Check all bowls, not just the first one in the case. A mismatched set can have different handling characteristics and may not meet the requirements for competition play.

Official World Bowls stamp

The official stamp records compliance with the applicable testing requirements and shows a validity year. World Bowls manufacturing and testing policy states that a compliant stamp is valid for a ten-year period ending on 31 December. If a stamp is unclear, out of date or important for your event, ask your national authority or an accredited tester rather than guessing.

Manufacturer or tester code

A letter in the stamp can identify the approved manufacturer or tester. World Bowls maintains a current manufacturer and tester list, including organisations that no longer operate.

Large and small rings

The small-ring side indicates the bias side; the bowl curves toward it. Get into the habit of checking the rings before every delivery so forehand and backhand are deliberate choices.

Grip and personal markings

Dimples and grooves are part of the grip. Coloured rings, emblems and team stickers help distinguish bowls, but competition rules can govern placement and matching. Do not alter a bowl in a way that changes its bias; only a licensed tester may perform that work.

Turn the markings into a better routine

Once you know the set, record your games and compare close heads with WGTS. Download it for iPhone or Android.

Rules note: eligibility can depend on current World Bowls laws, domestic regulations and the conditions of play for your event.