What design feature is characteristic of a scissor lift?

The characteristic design feature of a scissor lift is that the lift arms cross each other. This unique scissor mechanism allows for vertical movement as the arms expand and contract, effectively raising the platform to various heights. The crossing action of the arms provides stability and support, enabling the lift to reach significant elevations while maintaining balance. This design is what distinguishes scissor lifts from other types of aerial work platforms, as it allows for safer lifting with a larger, stable working area.

In contrast, extendable platforms are more commonly associated with boom lifts, which can reach out and up, rather than the vertical lift provided by scissor lifts. Rotating bases are also typically a feature of boom lifts that enable lateral movement, something not present in scissor lifts. Fixed height would suggest a lack of mobility and adaptability, which is not the intention of scissor lifts, as they are designed to raise and lower to accommodate different work scenarios.