I was about to order a new key at Citroen (115 euros) mine had no button, when acquired by conscience I check on amazon and there surprise ... not even 7 euros replacement hull. I specify, it comes without electronics it is necessary that your circuit is intact. the shell change is very easy, just transfer whatever is in the old and close with the screw provided. I'm not a pro, yet I did it in less than 5 minutes. The key works fine, there is not the Citroen logo on it but with my 100 euros saved, I pass easily. I highly recommend this product.
