EasyTouch Luer-Lock Syringe Barrel, 1ML Syringe, Pack of 100

Q: What is the outside diameter of the barrel?

A little less than a quarter-inch. Basically these are the same size as insulin syringes which are also 1ml, my boss uses them. These just have the luer-lok so you can use them with thicker, oil-based "depot" medications.

Q: What needle fits the barrel? You would think EasyTouch syringes would fit surprisingly they don't

I currently use Nipro and BD needles wit these syringes and have had no issues.

Q: What is the outside diameter in millimeters of the dispenser end of the unit?

I am not sure what the mm of the hub is. If you are looking for leur-lock end this it as syringe diameter is universal (I have never seen any different size needle hubs in over 30 years as a paramedic or RN). The only different style of a syringe is slip tip, which the needle slides onto the syringe.