Metric or imperial tackle, take your pick. We source tackle from all over the world. The US uses imperial measures, Asian-sourced tackle is mostly metric. New Zealand tackle has a partial hangover from it’s imperial past.
Tackle described in imperial measurements can look like this: 4oz sinker, 20lb line, 7′ fishing rod.
A 112g sinker sounds odd to New Zealand ears, so here we say 4 ounces. Fishing line IGFA (International Game Fishing Association) line classes are in kilograms: 1kg, 2kg, 3kg, 4kg, 6kg, 8 kg,10kg, 24kg, 37kg and 60kg. We find that, when people order standard “snapper” in the store, their order depends on age: baby boomers and older still ask for tackle in imperial. Even the young ones ask for 4oz sinkers.
Fishing rods are measured both in imperial and metric, but most are made to the base size of an old imperial measure: 6 feet , 7 feet, etc; rod guides and reel seats are usually metic.
Fishing reel spool capacities are recored in pounds and kilograms; some now have a braid rating and some have line diameter which comes in inch or millimetre increments. No wonder people get confused!
Shock leader, or trace, is mostly referenced in pounds, even thought it is usually from Asia. A crossover label reads “100lb breaking strain”, but you get a 30m roll.
Fishing hooks have their own measure system, sizing starting at the smallest: sizes 20, 18, 16, 14, 12, 10, 8, 6, 4, 2, 1 then 1/0, 2/0, 3/0, 4/0, 50, 6/0, 7/0, 8/0 upwards to the largest, 18/0. Fish hooks come in are different measures even though they are the same size rating, depending on manufacturer
With clients of all ages, from pre- or post-metric era (1987) buying tackle, any measurement unit is acceptable as the currency of tackle, as long as it works.