The H means that it is a High Pitch horn. A is not equal to 440 which is the current standard. A is a bit higher and the horn is set accordingly. I would look at the Conn dating information that has been posted here before. It sounds like it is a C melody from the C on the coding. Is it larger then a standard alto but smaller then a tenor? It is probabley not worth much as a player but it could be interesting as a collectable. I have a high pitch Alto from the 1880 neat horn, plays well with a good tone for early jazz. But very difficult to keep in tune with the rest of the guys. It is a fun horn but if you are looking for a player to gig with or do some other group work. Run Away Where did you find it? How much are they asking?