It's a nice lounge close to gate 53 at YUL international.
You can access it with the eligible TD Visa, Amex Plat, Priority Pass, direct payment (about $35) or by invitation (airlines like BA that do not have a lounge there).
What is offered as food and beverage is nothing spectacular, though. The lounge is very quiet and a good alternative if the MLL near gate 52 is too crowded with all eligible pax of AC, LX and LH.