一具 is read as いちぐ (ichigu) and means one set.
いちぐ
ichigu
どうぐいっしき
set of tools (implements)
こうちゃどうぐいっしき
tea set
おとつい
day before yesterday
いってい
fixed
おととし
year before last
いちだんらく
one paragraph
いちたいいち
one-to-one
いちぶ
one copy (e.g. of a document)
いちばん
best
いちめん
(on) the other hand
いちりゅう
school (e.g. of flower arrangement)
いっしゅ
sort of