What's the Difference Between a 3-way and 4-way Stopcock?

A 4-way stopcock allows for 360 degrees of rotation and has the states (shown below) for each of the four available positions. A 3-way stopcock has only three positions and has the first three states shown below.

In the first state, liquid flows between points A and B.
In the second, it flows between points A and C.
In the third, it flows between points B and C.
In the fourth state (4-way only), it flows between all three points.

While they are sold in the popular kit 14011, they are also sold separately:

• 14035-10–4-way Stopcock, Luer Lock (pkg. of 10)
• 14036-15–4-way Luer Stopcock (pkg. of 15)
• 14057-10–4-way Stockcok, Luer Lock, Blue (pkg. of 10)

See Selection