Start with the attachment points the job needs. For plain fall arrest, one dorsal D-ring at the back is enough, as on the Delta Plus HAR11 or the Karam Rhino PN11, PN21 and PN16. A second, sternal attachment at the chest, as on the Delta Plus HAR12, the Karam PN24 or the PN12 and PN32 with sternal loops, suits ladder and tower climbing on a vertical lifeline. Lateral D-rings on a waist belt are for work positioning: the Delta Plus HAR14 and the Karam PN31, PN41 and PN44 are listed to EN 358, and the Karam PN17 is a Class P positioning harness. A ventral D-ring, as on the Delta Plus PUMA HAR25 and the Karam PN56, PN57, Magna 3 and PN61, is for rope access and sitting in suspension; the Karam PN51 is a sit harness only and is not listed to EN 361 for fall arrest.
Then match the standard and load your site specifies. Delta Plus lists its harnesses to EN 361 for fall arrest, EN 358 for work positioning and EN 813 for rope access, at 140 kg for the HAR11, HAR12 and HAR14 and at 150 kg for the PUMA HAR25 so the weight of carried tools is covered. Karam states most of its models to EN 361:2002, EN 358:2018 and EN 813:2024, and many Rhino and Class models carry the ISI mark to IS 3521(Part 1):2021. For oil and gas rigs, the Karam FAP derrick and rig harnesses are stated to ANSI Z359.11-2021 and OSHA 1926.502, with hip lifting D-rings, sling seats and a removable belly belt for monkey board work.
Some sites need special webbing or hardware. Karam's Dienoc harnesses, PN22(DE) and PN42(01)(DE), have non-conductive D-rings and dielectric finished buckles for work near live electrical systems; the Flanil PN22FR and PN42(02)FR use flame retardant webbing with Kevlar stitching for welding and hot work; and the Nospark PN22(AS) uses antistatic webbing and lists ATEX 2014/34/EU for explosive atmospheres. The Revolta range has webbing that resists oil, water and dirt, the Elasto range uses stretch webbing that moves with the body, the Magna range adds breathable mesh padding, and the Rhino PN20 vest harness also comes in fluorescent green and fluorescent orange. For rescue, the Karam PN25 and PN45 add an overhead D-ring for lifting a worker out and are stated to EN 1497:2007, and the PN62 has a ventral rope clamp built in for climbing a rope.
Finally, decide between a harness on its own and a kit, and give the wearer's size. The Delta Plus ELARA kits pair a harness with a connector for the job: a 2 m energy absorbing webbing lanyard (ELARA190), a 2 m twin leg rope lanyard for scaffolding (ELARA280, and ELARA320 with a positioning lanyard), a 2.50 m or 10 m self retractable fall arrester for vertical work (ELARA140, ELARA270), a guided fall arrester on a 10 m or 20 m rope line for roofs (ELARA150, ELARA170) and a restraint kit that keeps the worker back from the edge (ELARA130V2). Karam's KI01 and KI02 come with a lanyard. Delta Plus offers the HAR11 and HAR12 in S/M/L and XL/XXL, the Karam Magna 1 and vest harness come in M and L, and Karam lists the sizes of several Rhino models, such as the PN31, PN41 and PN44, as (01), (02) and (03) versions.