Have used as an extension for my GSM BUG the holder. The only point he bothers me a bit is that the lithium cell 18650 very tightly seated in the bracket. The connecting cables are very thin but sufficient for my purpose. A change is as always a certain effort. Otherwise, I'm glad that I could replace the internal 300mA battery against external 3000mA cell and the service time of my GSM BUG to the factor 9 have increased (with tolerance). Now the GSM BUG has an operating time of about 30 days instead of 4 days. The product fulfills its purpose