Here's an IM set that can be either quick (800) or less quick (1600). It's the kind of set that carries you along and seems to be over before you know it. It also keeps you off balance in terms of how much rest you get after each swim.
Whichever version you choose, pick one sendoff that you can live with for the entire set. Even though the set is written with a line break after every 4 swims, ignore the breaks and swim the set straight through on your chosen sendoff. The line breaks are just to help you keep track of where you are in the set. Fins are OK. Focus on legal transitions and good body position in and out of each turn.
800 Version
16 X 50:
FL/FL
FL/BK
BK/BR
BR/FR
FL/BK
BK/BK
BK/BR
BR/FR
FL/BK
BK/BR
BR/BR
BR/FR
FL/BK
BK/BR
BR/FR
FR/FR
1600 Version
16 X 100
100 FL
50FL/50 BK
50BK/50 BR
50BR/50FR
50FL/50 BK
100BK
50BK/50 BR
50BR/50 FR
50FL/50BK
50BK/50BR
100 BR
50BR/50 FR
50FL/50BK
50BK/50 BR
50 BR/50 FR
100 FR
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