The Immunoglobulin Repeats 16-23 of Filamin A (FLNa) interact with numerous binding partners. Recent studies suggest that inter-domain interactions of these repeats under tension is crucial for the mechanosensing function of FLNa: the accessibility by FLNa binding partners is inhibited when the domain pairs are in closed conformation or permitted when they are in opened conformation. For example, it was proposed that in a closed stacked conformation, the A-strand of IgFLNa 20 interacts with the CD interface of IgFLNa 21, blocking its accessibility by other molecules such as b7 integrin tail and GP1Ba peptide. Prompted by these results, we examined the inter-domain interaction between repeats 20 and 21 (IgFLNa 20-21) using a magnetic tweezers setup. We show that the stacking between the two repeats can be disrupted at ∼15 pN at a loading rate range 0.1 - 2.1 pN/second and it can reform at decreased force values. Our results support the previously proposed force-dependent regulation of the accessibility of cryptic binding sites in the domain pair 20 and 21 of FLNa, which may have broad biological implications in the mechanisms of other mechanosensing proteins.