Marking center of bow limbs

[Interseptor]

Saw once where a bowyer used what looked a brick mason line to Mark the middle of limbs on a t/d bow.  He was drawing out the limbs before cutting.  He clipped the guide on each limb and it shot a lser down the middle to mark the center of the limbs.  Can anybody tell me what this device i called?

[kennym]

Not sure, but I have used a laser to mark, just mounted the laser up high and lined up marks at tips with mark at center to check. Still use a string tho, if the bow isn't perfectly level side to side, on a r/d or recurve, the laser can be off in the dips in limbs. JMO

[Crooked Stic]

Here is another way.
 

[Roy from Pa]

I use a string laser:) I find the center then draw my bow pattern off that.
 

[red hill]

A "string laser" ?! Ain't technology just somethin'? LOL
I heard that the ancient Mayans developed those.