The following are descriptions of various EOL market product attributes, as obtained from the EOL data dictionary.

CONSTANT_SPREAD_FLAG
An indicator that identifies whether the pricing for a product
maintains a constant difference between the bid and offer amounts.
Valid values are: (Y)es - a constant difference between the bid and
offer amounts is maintained; or (N)o - a constant difference between
the bid and offer amounts is not maintained. The default value is
N. In an example where the constant spread is .05, if the current
offer is 1.00 and a bid was placed for .96, the next offer would be
adjusted to 1.01.

LAST_TRADED_SPREAD_AMT
The offset amount added to or subtracted from the basis price for
the last trade. This spread is used for products whose price is based
on a published index. For example, Henry Hub + .10.

price_tick_size_amt
No explanation in Data Dictionary.

SPREAD_AMT
No explanation in Data Dictionary.

SPREAD_FLAG
No explanation in Data Dictionary.

TOP_BID_PRICE_AMT
Top bid price (saves join to stack by web-based online system)

TOP_OFFER_PRICE_AMT
Top offer price (saves join to stack by web-based online system)

volume_tick_size_qty
The number of units that the product is traded in, e.g. product
available in "lots" of 1000. Bids must be made in increments of the
tick size.