Marks USA Lock Numbers: Series 5 Mortise Locks, 175 Levers and 145 Deadlatches

A door schedule calls for 5RW96J/32D, or the building records show 175N/26D-234, and you need to know what the old lock is before ordering a replacement. Marks USA builds these numbers field by field, and its 2026/2027 price book sets the order for the three families below.

How to read a Marks mortise lock number

For mortise locksets the order is lock series, plate or rose design, knob or lever design, Marks function, a slash, the finish, a dash and the options. Taken apart, 5RW96J/32D reads:

Series 55 shares the body page with Series 5 and has a 2-1/2 inch backset; the rose page lists both under ANSI A156.13 Grade 1. Plates take two letters too, such as CL for Classic or NY for New Yorker. So 5CL92F/32D is a Series 5 lock on the Classic plate with the American lever, dormitory function F and satin stainless finish.

Lever and knob designs have their own codes: 92 American, 96 Titan, 86 Crescent and 82 Plaza, for example. On the rose pages the price book notes that 26D is not available with levers 82, 86, 92 and 96.

Function letters and option codes

The function letters are Marks' own, and the function pages add the ANSI number where there is one: N passage (F01), J classroom (F05), EW storeroom (F07), A entrance (F08, F10). F and FW are both dormitory functions, F12 and F13. They differ after the inside lever is turned: with F the outside stays locked, with FW the outside lever unlocks. Our lock functions guide covers passage, classroom, storeroom and entrance.

Options follow the dash, in alphanumeric order. A part number longer than 15 characters becomes a special number with the option field *1 and the options listed separately, and standard features need no code. A few codes from the mortise list:

For small and large format cores, see our SFIC vs LFIC guide.

Ordering only a Series 5 or 55 lock body

A lock body number leaves out the trim fields. The price book's example is 55JM/26D-T: a Series 55 body, JM hospital holdback function (F06), satin chrome, and option T for a 1-1/16 by 7-5/8 inch front. A 5J/32D-B4S6 reads the same way, a Series 5 classroom body with lever springs (B4) and a pair of strikes (S6).

The standard body has a 1-1/4 by 8 inch front, a full 1 inch bolt throw in stainless steel and a 3/4 inch anti-friction latch throw. The electrified functions EL (fail safe) and EU (fail secure) come only in Series 5 with the 2-3/4 inch backset; see our fail safe vs fail secure guide. For the cylinder cam, follow the Cam column on the function pages, for example 2101 for EW, 2102 for F and 2105 for J.

Marks 175 lever numbers

Cylindrical lock numbers skip the trim fields. The order is series, function, slash, finish, dash and options, as in the price book example 195AB/26D-G3. The 175 belongs to the 75 Line of Grade 2 Survivor leversets, with a 2-3/4 inch backset as standard; the Grade 1 95 Line page lists Series 195, 295 and 495. In 175N/26D-234, 175 is the series, N the passage function (ANSI F75) and 26D satin chrome (626).

The -234 at the end is not an option code in the price book. Other backsets on the 175 are latch options: E6 for 2-3/8 inch, E10 for 3-3/4 inch, E9 for 5 inch.

The 275 and 475 share the 75 Line page, whose picture shows the 175 with the American lever, the 275 with the Crescent and the 475 with the Titan. The page lists the 175 in finishes 26D and 19 and the other two in 26D. An R before the function letters, as in 175RF, marks the SFIC prep version for 6 or 7 pin cores, core not included. Under the heading American lever only, the price book lists ten F options for other makers' cylinders and IC cores, for example F19 for a Schlage 6 pin IC core.

Looking for an F92 lever? F92 is the ANSI number of the BS service station function, which the price book lists on the 95 Line page, not in the 175 table.

145 Defender deadlatch numbers

The 145 follows the same pattern, shown as 145K/32D-D1 (D1 is the option for a 2 inch door), and the order should also state keying, handing and door thickness. Marks lists the 145 as a Defender cylindrical cartridge deadlatch; the 130 is the Defender tubular deadbolt. The function letters:

• K: key outside, turnpiece inside
• M: double cylinder, key on either side
• L: communicating, key from one side only
• KL: key outside; the inside lever always opens the latch
• KK: cylinder by knob
• X: turnpiece inside, blank plate outside

The standard 145 has a Grade 1 latch with a 9/16 inch throw and a 2-3/4 inch backset, for a 2-1/8 inch bore and a 1-3/4 inch door. Option E11 changes the backset to 2-3/8 inch, as in 145K/32D-E11. The 145R models take an IC core, not included.

Marks gate locks are a separate group in the price book, with model numbers starting W37 (swinging) and W38 (sliding).

Finish, hand and the documents

The mortise finish table includes 3 polished brass (605), 10B dark bronze (613), 19 flat black (622), 26D satin chrome (626), 32D satin stainless steel (630) and AM, an antimicrobial finish. Our finish codes chart covers the BHMA numbers.

The price book treats handing as required information. Unless the order names the hand, locksets are supplied half LH and half RH, so put it on the order; the door handing chart shows how to name it.

Marks keeps its instruction sheets on the installation instructions page at marksusa.com, among them the I1 mortise lockset instructions and separate 145K and 145M Defender sheets. We did not find a sheet for the standard 175 leverset there. Door templates, the price book says, are available from Marks on request.

Browse our Marks Hardware brand page, or the Mortise Locks and Cylindrical and Tubular Locks categories.

Have a Marks number that does not fit these patterns? Our customer support team is available Monday - Friday, 8 AM - 4 PM Central Time, at 1-888-800-7789 or [email protected].