Workout

Warm-up (800)
100 swim, 200 kick, 200 pull, 100 IM 

Pre-set (500)
10 x 50's free on :50 (or 10 on :55, or 8 on 1:00) 

Pull-set (500)
5 x 100 (or 75's) free on 1:30
...5 cb on 2nd, 4th 100's 

Set (1600)
2 rounds - (2 x 4 x 200 on 3:30) 
25 stroke/175 free 
50 stroke/150 free 
75 stroke/125 free 
100 stroke/100 free 

Cool-down (400)
200 moderate kick 
200 EZ