Most orange strings use green wire (to blend into trees or foliage), with a few listings on white wire. Several sets specify a 22-gauge green wire.
Many orange LED strings are built for outdoor use and include features such as water-tight/coaxial connectors, weather-resistant PVC or polypropylene construction, and bulbs molded into sockets to improve water resistance.
Counts range from about 20 up to 100 bulbs. Lighted lengths vary widely—from as short as 6 inches up to several hundred inches (examples in listings include 288 in and 411 in).
Many sets are UL listed and include features like lamp-lock or replaceable-bulb sockets, spare replacement bulbs and fuses, and designs where the strand remains lit if one bulb fails.