The Jack
A jack must be 666grams plus or minus 10grams. The width must be 90.5mm plus or minus 0.5mm. The height must 98mm plus or minus 0.5mm. It must be 2 full bias and black or yellow in colour.
(There are many rules and regulations about what the jack looks like, how often is tested for conformance with the rules etc. See Appendix A – Laws Of The Game).
Bias
Bias is controlled by the shape of a wood or jack, not by weight.
Most bowls these days are manufactured with 2 full bias to match the jack. A 2-full bias bowl should follow the same line as a 2-full bias jack sent over the same distance ie finish directly in front of the jack!
Older woods might have a different bias and can still be used to play competitively.
The Bowl
A bowl must weigh at least 907gms and not more than 1.37kg. There are some medical dispensations but in all cases the diameter of the bowl must be at least 100mm.
The Footer
The footer must be round and have a diameter or not less that 125mm and not more than 155mm. There is no restriction on colour for a footer.
References From The Laws Of The Game
A.1. The game shall be played with standard Jacks of 2 full bias as approved by the British Crown Green Bowling Association. Jacks manufactured after 1st March 2004 shall be black or yellow in colour. They shall weigh 666grams plus or minus 10grams. The width shall be 90.5mm plus or minus 0.5mm. The height shall be 98mm plus or minus 0.5mm.
A ‘BOWL’ shall weigh not less than 907gms. (2lb), except that a player with medical evidence of a wasting disease of bone or muscle may be allowed a dispensation. The maximum weight of a bowl shall be 1.37kg (3lb). Where age is a consideration, a player may use a bowl under the 907gms limit if the bowl has a minimum profile of 100 mm. A bowl must not have any device for altering or adjusting the bias.
The ‘FOOTER’, which shall be round, shall have a diameter of not less than 125mm and not more than 155mm.