1. It is specially designed to protect the front end of the sensitive receiver from the high level RF influence of the mitted signal from nearby; 2. The SDR receiving antenna is very close to the mitting antenna, or the antenna support or other system faults lead to the high RF level entering the receiving antenna input, which will cause the SDR receiver to crash;Actual measurement: the distance between the receiving antenna and the mitting antenna is 10m, the mitting function is 1000W, and the SDR receiver can work normally. 3. Input and output: m female head; 4. Receive front-end protector only, 50 or 75 ohm compatible; 5. Protect your preamplifier and radio from excessive RF and anti-thunder Colour:As Shown Material:Aluminum Alloy Size: 25 x 25 x 112mm Weight: 82G Due to different batches, there may be differences in product appearance and printed text, which will not affect use Package Contents: 1 * SDR Receiver Protector Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm. Note: 1. Please allow 1-3 mm error due to manual measurement and 1-3g weight error make sure you don't mind before ordering. 2. Due to the lighting of the photos and the difference of monitors, the pictures may not reflect the actual color of the real item. Please make sure you don't mind before ordering, thank you! About Shipping: 1.please pay attention to your delivery address such as: name, street, house number, doorbell/email without name, etc. is correct, or the order will not be delivered correctly. 2.All items will be shipped within 3 business days after the payment is received. Most times you will receive them within 8-12 days then. The specific delivery time is depend on circumstances. 3.During the shopping process, if you have any questions, please feel free to consult us, we will reply you within 24 hours Hope you have a pleasant shopping experience!