refer to:
Any statement by declarer or a defender to the effect that a side will win a specific number of tricks is a claim of those tricks. A player also claims when he suggests that play be curtailed, or when he shows his cards (unless he demonstrably did not intend to claim - for example, if declarer faces his cards after an opening lead out of turn Law 54, not this Law, will apply).
"shows his cards" needs to have "to the non-claimimg side only". This is to cater for defender claims.