changed my car to a Citreon C4, then thought my Sat Nav was broken, as it didn't work in the car. Just before throwing it away, turned it on and had a full satelite signal, moved to inside the car and no signal, apparently the glass in the car prevented any signal from coming in. Checked it out and found that a external aeriel could be used. Checked it out on amazon job done, product arrived on time nicely packed and worked brilliantly. Thankyou.