4 tread GRP Glass Fibre Trade Swingback step ladders, every electrician should have a set of. Ideal for short duration work, in a spark risk environment. The combination of super-strong C-section glass fibre stiles and reinforced aluminium treads gives you a step that\'s electrically insulated to 35,000 volts . A durable yet lightweight and easy to handle step. Closed Height (m) 1.05. Open Height (m) 1 Rungs/Treads 4 Material Glass Fibre. Usage Type Heavy Duty. Warranty 5-Year. Standard EN131. Open Depth (m) 0.9. Weight (kg) 6