From Burlington and 128:

North on Route 3, take Route 129 exit (Chelmsford/Billerica)

At end of ramp, take a right

At second set of lights, take a left onto Mill Road (stay in left lane)

Follow Mill Road around to the left

About 1/16 of a mile, on your left "Quorum Office Park" 

Take a left into the park.

Take a right toward "269" ZOLL

From 495:

Take Route 3 S. to Route 129 exit (Chelmsford/Billerica)

At end of ramp, take a left at the set of lights, staying in left lane.

At next set of lights, take a left onto Mill Road (stay in left lane)

Follow Mill Road around to the left

About 1/16 of a mile, on your left "Quorum Office Park" 

Take a left into the park.

Take a right toward "269" ZOLL