Velvet's Blue string is their first which doesn't feature a silk core - it's a synthetic, which lowers cost while retaining the Velvet sound and feel. It has great articulation, big volume, great sustain and equal tension on all four strings (approx 25g per string.)
Fast response and nice volume.
Note that these strings do not have "Ball Ends" but rather loops on the tailpiece end of the strings. Looped bass strings (which are not as common as the ball ends we're used to seeing) are installed by wrapping the string around the hole in the tailpiece and back through the loop - similar to strings on a classical guitar.