1. Two section lengthening arm: the scope of use is relatively large, but its main function is to improve the excavation radius, such as river cleaning, land reclamation, subway entrance and exit excavation, pedestrian underground tunnel, expressway protective wall repair, general residential transportation of cement, etc. Some people also use his front breaking hammer to act on house demolition, but it is more dangerous. The two-stage lengthening arm is generally refitted in the interval of 10-26m.

2.三段式加长臂：或者多段式加长臂，主要应用于高层建筑的拆迁，前置破碎锤或者液压钳。20-28米内使用者比较多。

2. Three section lengthening arm: or multi section lengthening arm, which is mainly used for demolition of high-rise buildings, front crushing hammer or hydraulic tong. There are many users within 20-28 meters.

3.滑臂或者内伸缩臂：主要为了回转半径很小，但是挖掘深度要求很高的工况设计，一般会前置贝壳挖斗（贝形斗）。滑臂垂直挖掘深度一般为10米，内伸缩臂垂直挖掘深度一般在26米以内。

3. Sliding arm or inner telescopic arm: it is mainly designed for working conditions with small turning radius but high excavation depth requirements. Generally, it will be preceded by shell bucket (shell bucket). The maximum vertical excavation depth of the sliding arm is generally 10m, and the vertical excavation depth of the inner telescopic arm is generally within 26m.

4.打桩机加长臂：大小臂平直，前置弯臂2.6米左右（主要是为了与振动锤连接是便与阀块和管路的安装）及震动锤，应用于修建公路铁路或者埋设管道的时候打拔钢板桩。

4. Lengthening arm of pile driver: the big and small arms are straight, and the front bending arm is about 2.6m (mainly to connect with the vibrating hammer, which is convenient for the installation of valve block and pipeline) and the vibrating hammer. It is used to drive and pull out steel sheet piles when building roads and railways or burying pipelines.

5.抓木机、抓料机装卸煤机加长臂：更多的时候为了装卸火车或者汽车而设计，一般大臂7.6米，小臂5-6米.前置抓木器、抓钳器或者贝壳挖斗。

5. Wood grabbing machine, material grabbing machine and coal handling machine lengthening arm: more often, it is designed for loading and unloading trains or cars. Generally, the big arm is 7.6m and the small arm is 5-6m. The front wood grabber, gripper or shell bucket.