I take it you've decided to go ahead & get the unit, in spite of it being a discontinued model. Now you'll want to read through this sticky & check out some of the links provided, and the graphs & pics that explain the workings & capabilities.
I have mine mounted on the trolling motor, and was lucky enough to have received the mounting sleeve in the package deal I made with the member that sold me the unit. I believe this mounting sleeve now comes packaged with the unit. That's a $20+ savings, if you intend to mount yours on the TM.
Unfortunately, that particular card/reader is no longer available, but you can still get the micro-sd card, adapter card, and a reader for near the same money. You may just have to do a little shopping around to find some place that offers them ... or, since you have a reader, just get the micro-sd card & adapter. And you won't need the card to update the unit, since the unit will likely already have the updated software version installed. Your card will allow you to take screenshots, though, and that can prove very useful in showing what you're seeing on the unit, in the event there's a problem or if you just want some advice on settings tweaks.
One thing you will want to do, is to print out the Operations Manual from this link :
http://www.lowrance.com/Root/Lowranc...0153-001_w.pdf ... because the "instructions" papers that come with the unit are mostly skewed towards the installation of the unit & transducer, and don't really show you much about how it operates.
And, of course, ask any questions you have ... right here ... and we'll try & guide you along to getting the best performance out of it. And don't worry about how trivial your questions may seem to you, as the answers may be beneficial to all who already have the unit or are considering getting it.
... cp