新加坡采购需求：扭簧

I'm looking for a double torsion spring with specific requirements. The outer diameter should be around 3mm, and the free length needs to be approximately 25mm. Ideally, I would like the spring to have 4 or more coils to ensure adequate functionality. The material should be 55CrSi or a material with equivalent strength properties to guarantee durability and performance in an industrial setting. Additionally, I am interested in any finishing options that could enhance the longevity of the spring. It's crucial that this spring can withstand industrial usage, so please provide details on the manufacturing capabilities, lead times, and any available options that meet these specifications. Thank you!