Absence of infinite cluster for critical Bernoulli percolation on slabs

We prove that for Bernoulli percolation on a graph ${\mathbb{Z}}^2\times \{0,\dots ,k\}$ ($k\ge 0$), there is no infinite cluster at criticality, almost surely. The proof extends to finite range Bernoulli percolation models on ${\mathbb{Z}}^2$ which are invariant under $\pi \mathrm{/}2$-rotation and reflection.