Airsoft Masterpiece Sear Spring
Far better than the Stock Sear (Leaf) Spring.
Due to it being made of steel it holds its shape far better than stock TM ones.
This is definitely needed if you are planning on tuning your trigger to be short and crisp.
This is one of the best Sear springs out there due to it's perfect tolerances, no need to shave down to fit in your grip.