used in the middle and hard rock(f=8-18). Key Specifications Product Details: Place of Origin Zhejiang, China (Mainland) Brand Name JUSHAN Model Number YT-24 STANDARD ISO9001:2000 Payment & Shipping Terms: Minimum Order Quantity: 1 Set/Sets Packaging Details: carton Delivery Time: 10 days Payment Terms: L/C,T/T,Western Union Supply Ability: 1000 Set/Sets per Month