1♣/1♢ – (1♡) – x

1/1 – (1) – x

N
W   E
 
S
Q 10 8 5
A 4 2
10 6 5 2
K 9 8

Dealer:

West

W N E S
1 1 Double

When opponents bid 1 over opener's 1 or 1, a double shows exactly 4 cards in spades and 6+ points.

It doesn't show the other minor.

With 5+ spades we bid 1. We leverage the overcall to be more precise about our spade length.