  SX Phoenicis (SXP) variables are short period pulsating stars that exhibit a
period-luminosity (PL) relation. We derived the gri-band PL and extinction-free
period-Wesenheit (PW) relations, as well as the period-color (PC) and
reddening-free period-Q-index (PQ) relations for 47 SXP stars in located in 21
globular clusters using the optical light curves taken from Zwicky Transient
Facility (ZTF). These empirically relations were derived for the first time in
the gri filters except for the g-band PL relation. We used our gi band PL and
PW relations to derive a distance modulus to Crater II dwarf spheroidal which
hosts one SXP variable. Assuming that the fundamental and first-overtone
pulsation mode for the SXP variable in Crater II, we found distance moduli of
$20.03 \pm 0.23$ mag and $20.37 \pm 0.24$ mag, respectively, using the PW
relation, where the latter is in excellent agreement with independent RR Lyrae
based distance to Crater II dwarf galaxy.
