I am a novice GPS user and purchased the 1:50 UK map on a sim supplied by Martin. Delivery was fast and instructions were clear and very straightforward. I am using the mapping on a Garmin Etrex 35 touch. The detail is really good and I have already got my head round using the map in Garmin Basecamp. GPS is proving to be a great safety tool alongside my map and compass. Thank you Martin for excellent service and an excellent product.