AB Workouts and Pecks

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Ok I am going straight to the point. I work out regularly but have slacked off recently because of traveling for work. (i.e being a consulting mechanical engineer). I am trying to get my 6 pack back and nice pecks so I can feel good about walking around without a shirt on and fitting in my shirts better. I am looking for workouts that I can do while on the road or at home without weights? Suggestions are appreciated but I know particulars about certain routines so please do not post bull**** on here.

Thank you,

Feel free to add me and message me suggestions too. I try to run on a regular basis too.