The 686/586 is the top of the line .357 magnum revolver made by Smith & Wesson. It is an L-frame revolver (all other .357 are k-frame except the 27) with a full underlug barrel. The 686 is stainless, the 586 blue.
The gun is very strong and very reliable. It would digest a steady diet of .357 round without any problem. It comes with an adjustable rear sight and either a fixed red ramp front sight or an adjustable front sight. You can also have a target trigger installed.
I found it to be very accurate and very fun too shoot. The trigger pull is very good in my opinion both in SA and DA mode. It is one of the best .357 handgun available. Some are maybe a bit better (the wonderful Colt Python for example) but it is certainly among the best quality/money rate.