Add to Cart Quick view Collins 353A-15 Plug In Mechanical Filter Adapter for the National HRO-60 & Hammarlund SP-400 Receivers Collins MSRP: Now: $74.99 Was: This Collins 353A-15 Plug In Mechanical Filter Adapter Set, is made for the National HRO-60 & Hammarlund SP-400 Receivers. This Filter Adapters is for 1.5 KC bandwidth. It looks to be in excellent shape and it simply plug into one of the IF... MSRP: Now: $74.99 Was: Add to Cart Quick view Qty in Cart: 0 Quantity: Decrease Quantity: Increase Quantity: Price: MSRP: Now: $74.99 Was: Subtotal: Add to Cart