The Salter spring balance consists of a strong helical spring housed inside a metal or transparent casing, with a hook at the bottom to suspend loads. When a load is applied, the spring stretches, and the extension is directly proportional to the force applied.Here's an overview of a Spring Balance Metric (Salter) and its functionality. spring balance is an instrument that measures weight or force using a spring, where the force is determined by how much the spring stretches or compresses under load.