protected function prepare_value( $post_id = null ) {
			$post_id = $post_id ?? get_the_ID();
			$value   = trim(
				sprintf(
					'%s %s %s',
					invp_get_the_year( $post_id ),
					invp_get_the_make( $post_id ),
					invp_get_the_model( $post_id )
				)
			);
			$trim    = invp_get_the_trim( $post_id );
			if ( ! empty( $trim ) ) {
				$value .= ' ' . $trim;
			}
			$stock_number = invp_get_the_stock_number( $post_id );
			if ( ! empty( $stock_number ) ) {
				$value .= ', ' . $stock_number;
			}
			return $value;
		}