Z-Metal Tank

Level 4 LIGHT/Machine Union Effect
1500 ATK / 1300 DEF

Once per turn, you can either: Target 1 "X-Head Cannon" or "Y-Dragon Head" you control; equip this card to that target, OR: Unequip this card and Special Summon it. A monster equipped with this card gains 600 ATK/DEF, also if the equipped monster would be destroyed by battle or card effect, destroy this card instead.

Rulings – Yugipedia

Printings:

Magician's Force: MFC-006 (Super Rare) - 2003-10-10
Dark Revelation Volume 1: DR1-EN061 (Rare) - 2005-03-19
Duelist Pack: Chazz Princeton: DP2-EN007 (Common) - 2006-02-08
Duelist Pack: Kaiba: DPKB-EN012 (Common) - 2010-04-16
Structure Deck: Seto Kaiba: SDKS-EN007 (Common) - 2016-10-20
Legendary Collection Kaiba Mega Pack: LCKC-EN007 (Ultra Rare) - 2018-03-08
Speed Duel: Battle City Box: SBCB-EN065 (Common) - 2020-11-26
25th Anniversary Ultimate Kaiba Set: KC01-EN029 (Ultra Rare) - 2024-03-01

Prices:

Cardmarket: 0.15 €
TCGplayer: $ 0.14