  Using four different experimental techniques, we performed comprehensive
studies of the bulk superconductive properties of single crystals of the nearly
optimally doped $Ba_{1-x}K_xFe_2As_2$ ($T_{c} \approx 36\,K$), a typical
representative of the 122 family. We investigated temperature dependencies of
the (i) specific heat $C_{el}(T)$, (ii) first critical magnetic field
$H_{c1}(T)$, (iii) intrinsic multiple Andreev reflection effect (IMARE), and
(iv) infrared reflectivity spectra. All data clearly show the presence of (at
least) two superconducting nodeless gaps. The quantitative data on the
superconducting spectrum obtained by four different techniques are consistent
with each other: (a) the small energy gap $\Delta_S(0) \approx 1.8 - 2.5\,meV$,
and the large gap energy $\Delta_L(0) \approx 9.5 - 11.3\,meV$ that
demonstrates the signature of an extended s-wave symmetry ($\sim~33 \%$
in-plane anisotropy), (b) the characteristic ratio $2\Delta_L/k_BT_C$
noticeably exceeds the BCS value.
