These strings have been made for decades; they have a nyloncore, which is flatwound with nylon on the G and D strings, and with monel (a nickel alloy) on the A and E strings. The strings have a comfortable soft feel,with a lighter tension than most steel strings, and good tone and volume.
Rotosound indicates that they are good for many styles of music, including jazz, rockabilly, bluegrass, and contemporary styles. They are flexible and durable enough for comfortable slapping, but some players report that they havea sort of "boingy" (like an elastic band) sound under heavy slapping. The top strings have kind of a "tan" color to the wrapping,so they almost appear to be gut strings from a distance. They have a light feelbut still have a warm tone. You might consider this set to be a alternative to gut strings if you want some of that flavor -- but with more definition and longer sustain than real gut.
You can bow them, but there are far better arco strings out there. For asimilar pizz "vibe" with better bowability, consider the PirastroObligatos.
Also note that these strings do not have "Ball Ends" but rather loopson 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 tostrings on a classical guitar.
Rotosound does not list gauges on their packages, but I have taken the time togauge all the strings using a digital caliper and present the following unofficial measurements of the "Superb" set for your reference:
That's no typo, the D is the biggest string in the set; theE and A are wrapped in a nickel alloy and thereby have more mass, so they'renot as thick.