Each model of CS 33ET, TCS-3301PFS and PMS-3301PFS is an environmentally-friendly engine chain saw that reduces gas emissions with a catalytic muffler. The handle is covered with soft material and optimally shaped for high level of reliable operability and stable balance. Moreover, a thumb rest (concave part) is provided at the joint between the rear and front handle to ensure stable operation in any direction. The case is strong enough to withstand heavy shocks during operation thanks to a smooth surface and the honeycomb construction ventilator window.