Hardware prefetching is an important feature of modern high-performance processors. When the application working set is too large to fit in on-chip caches, disabling hardware prefetchers may result in severe performance reduction. A new prefetcher was recently introduced, the Sandbox prefetcher, that tries to find dynamically the best prefetch offset using the sandbox method. The Sandbox prefetcher uses simple hardware and was shown to be quite effective. However, the sandbox method does not take into account prefetch timeliness. We propose an offset prefetcher with a new method for selecting the prefetch offset that takes into account prefetch timeliness. We show that our Best-Offset prefetcher outperforms the Sandbox prefetcher on the SPEC CPU2006 benchmarks , with equally simple hardware.