Are they legal, or are they considered to offer a marked string?
I like my black and yellow string, but if there is any doubt I'd rather make up some single colour strings now...
Recurve fita rules state
7.3.1.2 A bowstring of any number of strands,
7.3.1.2.1 which may be of different colours and of the material chosen for
the purpose. It may have a center serving to accommodate the
drawing fingers, a nocking point to which may be added serving(
s) to fit the arrow nock as necessary, and, to locate this
point, one or two nock locators may be positioned. At each end
of the bowstring there is a loop which is placed in the string
nocks of the bow when braced. In addition one attachment is
permitted on the string to serve as a lip or nose mark. The serving
on the string must not end within the athlete?s vision at full
draw. The bowstring must not in any way assist aiming through
the use of a peephole, marking, or any other means.
compound fita rules state
7.3.3.2 A bowstring of any number of strands,
7.3.3.2.1 which may be of different colours and of the material chosen for
the purpose. It may have a center serving to accommodate the
drawing fingers or release aid. Nocking points may be fitted to
which may be added serving(s) to fit the arrow nock as necessary.
To locate these points one or two nock locators may be fitted.
In addition attachments are permitted on the string such as a
lip or nose mark, a peep-hole, a peep-hole ?hold-in-line? device,
loop bowstring, etc.
fita std bow states
7.3.2.1.1 The bowstring material may not be of a higher specification than
Dacron.
so as you can see they both allow different colours