Tex. Tax Code § 151.3565

(a) The sale of an emergency preparation item is exempted from the taxes imposed by this chapter if the sale takes place during a period beginning at 12:01 a.m. on the Saturday before the last Monday in April and ending at 12 midnight on the last Monday in April.

(b) For purposes of this section, "emergency preparation item" means:

(1) a portable generator used to provide light or communications or to preserve perishable food in the event of a power outage, the sales price of which is less than $3,000;

(2) an item listed in this subdivision, the sales price of which is less than $300:

(A) a storm protection device manufactured, rated, and marketed specifically to prevent damage to a glazed or non-glazed opening during a storm; or

(B) an emergency or rescue ladder; or

(3) an item listed in this subdivision, the sales price of which is less than $75:

(A) a reusable or artificial ice product;

(B) a portable, self-powered light source;

(C) a gasoline or diesel fuel container;

(D) a AAA cell, AA cell, C cell, D cell, 6 volt, or 9 volt battery, or a package containing more than one battery, other than an automobile or boat battery;

(E) a nonelectric cooler or ice chest for food storage;

(F) a tarpaulin or other flexible waterproof sheeting;

(G) a ground anchor system or tie-down kit;

(H) a mobile telephone battery or battery charger;

(I) a portable self-powered radio, including a two-way radio or weatherband radio;

(J) a fire extinguisher, smoke detector, or carbon monoxide detector;

(K) a hatchet or axe;

(L) a self-contained first aid kit; or

(M) a nonelectric can opener.