1♠ – (2♣/2♢) – x

1 – (2/2) – x

N
W   E
 
S
Q 8
K J 10 5
K 8 6 5
9 8 6

Dealer:

West

W N E S
1 2 Double

When opponents bid 2 or 2 over opener's 1, a double shows 4 cards in hearts and 8+ points.

Note that without the intervention we would not be able to immediately show a 4-card heart suit at all, because 1– 2 shows 5+ hearts (and 10+ points). Again, we leverage the intervention to help describe our hand.

A double might show a 5-card heart suit and less than 10 points.